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Posted to commits@jmeter.apache.org by vl...@apache.org on 2025/10/31 09:04:24 UTC

(jmeter) 02/02: style: resolve issues identified by errorprone

This is an automated email from the ASF dual-hosted git repository.

vladimirsitnikov pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/jmeter.git

commit 47bd32e0aa2d804a196570c05b52e88aabdc7e4f
Author: Vladimir Sitnikov <si...@gmail.com>
AuthorDate: Thu Oct 30 20:24:52 2025 +0300

    style: resolve issues identified by errorprone
---
 .../org/apache/jmeter/util/BeanShellClient.java    |   2 +-
 .../assertions/CompareAssertionBeanInfo.java       |  14 +-
 .../apache/jmeter/assertions/HTMLAssertion.java    |   4 +-
 .../jmeter/assertions/JSONPathAssertion.java       |   7 +-
 .../jmeter/assertions/ResponseAssertion.java       |  34 +---
 .../apache/jmeter/assertions/SMIMEAssertion.java   |   6 +-
 .../apache/jmeter/assertions/SizeAssertion.java    |  25 +--
 .../org/apache/jmeter/assertions/XMLAssertion.java |   2 +-
 .../jmeter/assertions/XMLSchemaAssertion.java      |  18 +-
 .../apache/jmeter/assertions/gui/AssertionGui.java |   5 +-
 .../assertions/gui/DurationAssertionGui.java       |   6 +-
 .../assertions/gui/JSONPathAssertionGui.java       |   6 +-
 .../jmeter/assertions/gui/MD5HexAssertionGUI.java  |   6 -
 .../jmeter/assertions/gui/XPath2AssertionGui.java  |   3 +-
 .../jmeter/assertions/gui/XPathAssertionGui.java   |   3 +-
 .../assertions/jmespath/JMESPathAssertion.java     |   3 -
 .../jmespath/gui/JMESPathAssertionGui.java         |   6 +-
 .../java/org/apache/jmeter/config/CSVDataSet.java  |   4 +-
 .../apache/jmeter/config/CSVDataSetBeanInfo.java   |  36 ++--
 .../jmeter/config/KeystoreConfigBeanInfo.java      |  12 +-
 .../apache/jmeter/config/RandomVariableConfig.java |  10 +-
 .../config/RandomVariableConfigBeanInfo.java       |  18 +-
 .../apache/jmeter/control/ForeachController.java   |   2 +-
 .../control/gui/CriticalSectionControllerGui.java  |   6 +-
 .../jmeter/control/gui/ForeachControlPanel.java    |   3 +-
 .../jmeter/control/gui/ModuleControllerGui.java    |   2 +-
 .../apache/jmeter/extractor/BoundaryExtractor.java |   2 +-
 .../extractor/DebugPostProcessorBeanInfo.java      |  32 ++--
 .../org/apache/jmeter/extractor/HtmlExtractor.java |   2 +-
 .../apache/jmeter/extractor/RegexExtractor.java    |   8 +-
 .../apache/jmeter/extractor/XPath2Extractor.java   |   2 +-
 .../apache/jmeter/extractor/XPathExtractor.java    |   2 +-
 .../jmeter/extractor/gui/BoundaryExtractorGui.java |   6 +-
 .../jmeter/extractor/gui/HtmlExtractorGui.java     |   6 +-
 .../jmeter/extractor/gui/RegexExtractorGui.java    |   6 +-
 .../jmeter/extractor/gui/XPath2ExtractorGui.java   |   3 +-
 .../jmeter/extractor/gui/XPathExtractorGui.java    |   3 +-
 .../extractor/json/jmespath/JMESPathCache.java     |   4 +-
 .../json/jmespath/gui/JMESPathExtractorGui.java    |   3 +-
 .../extractor/json/jsonpath/JSONManager.java       |   4 +-
 .../json/jsonpath/gui/JSONPostProcessorGui.java    |   3 +-
 .../json/render/AbstractRenderAsJsonRenderer.java  |   6 +-
 .../action/ExportTransactionAndSamplerNames.java   |   5 +-
 .../org/apache/jmeter/modifiers/SampleTimeout.java |   3 +-
 .../apache/jmeter/modifiers/UserParameters.java    |   2 +-
 .../jmeter/modifiers/gui/CounterConfigGui.java     |   3 +-
 .../org/apache/jmeter/reporters/MailerModel.java   |  14 +-
 .../jmeter/sampler/DebugSamplerBeanInfo.java       |  24 +--
 .../jmeter/timers/ConstantThroughputTimer.java     |  10 +-
 .../timers/ConstantThroughputTimerBeanInfo.java    |   5 +-
 .../java/org/apache/jmeter/timers/SyncTimer.java   |  12 +-
 .../apache/jmeter/timers/SyncTimerBeanInfo.java    |   4 +-
 .../ConstantPoissonProcessGenerator.java           |   4 +-
 .../PreciseThroughputTimerBeanInfo.java            |  16 +-
 .../ComponentTreeClonerForValidation.java          |   3 +-
 .../jmeter/visualizers/ComparisonVisualizer.java   |   4 +-
 .../jmeter/visualizers/MailerVisualizer.java       |   3 +-
 .../visualizers/RenderAsBoundaryExtractor.java     |   4 +-
 .../jmeter/visualizers/RenderAsCssJQuery.java      |   2 +-
 .../apache/jmeter/visualizers/RenderAsHTML.java    |  25 +--
 .../apache/jmeter/visualizers/RenderAsJSON.java    |  10 +-
 .../org/apache/jmeter/visualizers/RenderAsXML.java |  43 ++---
 .../apache/jmeter/visualizers/RenderAsXPath.java   |   2 +-
 .../apache/jmeter/visualizers/RenderAsXPath2.java  |   2 +-
 .../apache/jmeter/visualizers/RenderInBrowser.java |   3 -
 .../apache/jmeter/visualizers/RequestViewRaw.java  |  18 +-
 .../jmeter/visualizers/RespTimeGraphChart.java     |   2 +-
 .../visualizers/RespTimeGraphVisualizer.java       |  10 +-
 .../jmeter/visualizers/SamplerResultTab.java       |  28 +--
 .../jmeter/visualizers/SearchTextExtension.java    |   2 +-
 .../apache/jmeter/visualizers/SearchTreePanel.java |   4 +-
 .../jmeter/visualizers/StatGraphVisualizer.java    |  15 +-
 .../apache/jmeter/visualizers/StatVisualizer.java  |   4 +-
 .../jmeter/visualizers/TreeNodeRenderer.java       |   4 +-
 .../visualizers/ViewResultsFullVisualizer.java     |  14 +-
 .../visualizers/XMLDefaultMutableTreeNode.java     |  24 +--
 .../visualizers/backend/BackendListener.java       |  10 +-
 .../visualizers/backend/BackendListenerGui.java    |   3 -
 .../jmeter/visualizers/backend/ErrorMetric.java    |   3 +-
 .../graphite/PickleGraphiteMetricsSender.java      |  13 --
 .../graphite/TextGraphiteMetricsSender.java        |   9 -
 .../backend/influxdb/HttpMetricsSender.java        |  10 +-
 .../jmeter/assertions/SizeAssertionTest.java       |   6 +-
 .../jmeter/assertions/TestJSONPathAssertion.java   |  27 +--
 .../jmeter/assertions/XMLSchemaAssertionTest.java  |   4 +-
 .../jmeter/assertions/XPathAssertionTest.java      |   4 +-
 .../apache/jmeter/assertions/XmlAssertionTest.java |   7 +-
 .../assertions/jmespath/TestJMESPathAssertion.java |  22 ++-
 .../org/apache/jmeter/config/TestCVSDataSet.java   |   2 +-
 .../apache/jmeter/control/TestWhileController.java |   6 +-
 .../jmeter/extractor/TestRegexExtractor.java       |  15 +-
 .../jmeter/extractor/TestXPathExtractor.java       |   2 +-
 .../json/jmespath/TestJMESPathExtractor.java       |  53 ++++--
 .../org/apache/jmeter/timers/SyncTimerTest.java    |   4 +-
 .../jmeter/visualizers/TestSampleCompareTo.java    |   2 +-
 .../backend/SamplerMetricFixedModeTest.java        |  16 +-
 .../backend/SamplerMetricTimedModeTest.java        |  12 +-
 .../backend/influxdb/HttpMetricsSenderTest.java    |   6 +-
 .../src/main/java/org/apache/jmeter/JMeter.java    | 208 ++++++++++-----------
 .../java/org/apache/jmeter/ProxyAuthenticator.java |  11 +-
 .../jmeter/assertions/CompareAssertionResult.java  |   6 +-
 .../apache/jmeter/config/gui/ArgumentsPanel.java   |   7 +-
 .../apache/jmeter/config/gui/RowDetailDialog.java  |  27 ++-
 .../apache/jmeter/control/GenericController.java   |  12 +-
 .../org/apache/jmeter/control/IfController.java    |  18 +-
 .../java/org/apache/jmeter/control/RunTime.java    |   2 +-
 .../jmeter/control/TransactionController.java      |   3 +-
 .../jmeter/control/gui/IfControllerPanel.java      |   6 +-
 .../jmeter/control/gui/LoopControlPanel.java       |  12 +-
 .../org/apache/jmeter/control/gui/RunTimeGui.java  |  12 +-
 .../org/apache/jmeter/control/gui/TestPlanGui.java |   6 +-
 .../jmeter/control/gui/WhileControllerGui.java     |  12 +-
 .../apache/jmeter/control/gui/WorkBenchGui.java    |   3 +-
 .../apache/jmeter/engine/ClientJMeterEngine.java   |  13 +-
 .../org/apache/jmeter/engine/ConvertListeners.java |   4 +-
 .../java/org/apache/jmeter/engine/PreCompiler.java |  22 +--
 .../jmeter/engine/RemoteJMeterEngineImpl.java      |   4 -
 .../apache/jmeter/engine/StandardJMeterEngine.java |  22 +--
 .../java/org/apache/jmeter/engine/TreeCloner.java  |   4 +-
 .../org/apache/jmeter/engine/TurnElementsOn.java   |   4 +-
 .../jmeter/engine/util/CompoundVariable.java       |  10 +-
 .../apache/jmeter/engine/util/FunctionParser.java  |  18 +-
 .../apache/jmeter/engine/util/ValueReplacer.java   |   3 +-
 .../jmeter/functions/gui/FunctionHelper.java       |   2 +-
 .../jmeter/gui/AbstractJMeterGuiComponent.java     |   2 +-
 .../java/org/apache/jmeter/gui/GuiPackage.java     |  15 +-
 .../java/org/apache/jmeter/gui/HtmlReportUI.java   |  52 +++---
 .../java/org/apache/jmeter/gui/LoggerPanel.java    |   3 -
 .../main/java/org/apache/jmeter/gui/MainFrame.java |  13 +-
 .../main/java/org/apache/jmeter/gui/NamePanel.java |  16 +-
 .../apache/jmeter/gui/action/AbstractAction.java   |  27 ++-
 .../java/org/apache/jmeter/gui/action/Clear.java   |   7 +-
 .../gui/action/CompileJSR223TestElements.java      |   8 +-
 .../java/org/apache/jmeter/gui/action/Copy.java    |   3 -
 .../org/apache/jmeter/gui/action/Duplicate.java    |   3 -
 .../java/org/apache/jmeter/gui/action/Help.java    |  13 +-
 .../jmeter/gui/action/LoadRecentProject.java       |  45 ++---
 .../java/org/apache/jmeter/gui/action/Save.java    |   2 +-
 .../org/apache/jmeter/gui/action/SaveGraphics.java |   4 +-
 .../apache/jmeter/gui/action/SearchTreeDialog.java |   6 +-
 .../java/org/apache/jmeter/gui/action/Start.java   |  17 +-
 .../apache/jmeter/gui/action/StopStoppables.java   |   9 -
 .../action/validation/TreeClonerForValidation.java |   6 +-
 .../apache/jmeter/gui/logging/LogEventObject.java  |   4 +-
 .../jmeter/gui/menu/StaticJMeterGUIComponent.java  |   2 +-
 .../apache/jmeter/gui/tree/JMeterTreeModel.java    |   3 +-
 .../jmeter/gui/tree/JMeterTreeTransferHandler.java |   2 +-
 .../org/apache/jmeter/gui/util/FileDialoger.java   |   2 +-
 .../gui/util/HeaderAsPropertyRendererWrapper.java  |   3 +-
 .../apache/jmeter/gui/util/HorizontalPanel.java    |   4 +-
 .../org/apache/jmeter/gui/util/JDateField.java     |   6 +-
 .../org/apache/jmeter/gui/util/JMeterMenuBar.java  |  13 +-
 .../org/apache/jmeter/gui/util/JMeterToolBar.java  |  27 ++-
 .../jmeter/gui/util/NumberFieldErrorListener.java  |   8 +-
 .../apache/jmeter/gui/util/PowerTableModel.java    |   2 +-
 .../jmeter/gui/util/TextAreaTableCellEditor.java   |   4 +-
 .../apache/jmeter/gui/util/TristateCheckBox.java   |  18 +-
 .../org/apache/jmeter/gui/util/VerticalPanel.java  |   4 +-
 .../config/ReportGeneratorConfiguration.java       |   8 +-
 .../report/core/ControllerSamplePredicate.java     |   7 -
 .../java/org/apache/jmeter/report/core/Sample.java |   5 -
 .../apache/jmeter/report/core/SampleMetadata.java  |   5 -
 .../report/dashboard/AbstractDataExporter.java     |  21 +--
 .../report/dashboard/HtmlTemplateExporter.java     |  28 +--
 .../jmeter/report/dashboard/JsonExporter.java      |   3 +-
 .../jmeter/report/dashboard/JsonizerVisitor.java   |  21 ---
 .../jmeter/report/dashboard/TemplateVisitor.java   |  12 --
 .../processor/AbstractAggregatorFactory.java       |  20 --
 .../report/processor/AbstractSampleProcessor.java  |  27 ---
 .../report/processor/AbstractSampleSource.java     |  38 ----
 .../report/processor/AbstractSummaryConsumer.java  |  17 --
 .../jmeter/report/processor/AggregateConsumer.java |  17 --
 .../report/processor/ApdexSummaryConsumer.java     |  22 ---
 .../report/processor/CsvFileSampleSource.java      |  27 +--
 .../report/processor/ErrorsSummaryConsumer.java    |  34 ----
 .../jmeter/report/processor/ListResultData.java    |  15 --
 .../jmeter/report/processor/MapResultData.java     |  10 -
 .../jmeter/report/processor/MaxAggregator.java     |  20 --
 .../report/processor/MaxAggregatorFactory.java     |   7 -
 .../jmeter/report/processor/MeanAggregator.java    |  20 --
 .../report/processor/MeanAggregatorFactory.java    |   7 -
 .../report/processor/MedianAggregatorFactory.java  |   7 -
 .../jmeter/report/processor/MinAggregator.java     |  20 --
 .../report/processor/PercentileAggregator.java     |  20 --
 .../processor/PercentileAggregatorFactory.java     |   7 -
 .../report/processor/RequestsSummaryConsumer.java  |  11 --
 .../processor/StatisticsSummaryConsumer.java       |  29 ---
 .../jmeter/report/processor/SumAggregator.java     |  20 --
 .../report/processor/SumAggregatorFactory.java     |   7 -
 .../report/processor/TimeRateAggregator.java       |  20 --
 .../processor/TimeRateAggregatorFactory.java       |   7 -
 .../processor/Top5ErrorsBySamplerConsumer.java     |  21 ---
 .../jmeter/report/processor/ValueResultData.java   |  10 -
 .../processor/graph/AbstractGraphConsumer.java     |  29 +--
 .../graph/AbstractOverTimeGraphConsumer.java       |  18 --
 .../processor/graph/AbstractSeriesSelector.java    |   6 -
 .../graph/AbstractVersusRequestsGraphConsumer.java |  54 +-----
 .../report/processor/graph/CodeSeriesSelector.java |   7 -
 .../processor/graph/ConnectTimeValueSelector.java  |   7 -
 .../processor/graph/ElapsedTimeValueSelector.java  |   5 -
 .../processor/graph/IndexedNameSelector.java       |   7 -
 .../processor/graph/LatencyValueSelector.java      |   7 -
 .../report/processor/graph/NameSeriesSelector.java |   7 -
 .../processor/graph/StaticSeriesSelector.java      |   7 -
 .../processor/graph/StatusSeriesSelector.java      |   7 -
 .../processor/graph/TimeStampKeysSelector.java     |   7 -
 .../graph/impl/ActiveThreadsGraphConsumer.java     |  13 --
 .../graph/impl/BytesThroughputGraphConsumer.java   |  13 --
 .../graph/impl/CodesPerSecondGraphConsumer.java    |  13 --
 .../impl/ConnectTimeOverTimeGraphConsumer.java     |  13 --
 .../processor/graph/impl/CustomGraphConsumer.java  |  13 --
 .../graph/impl/HitsPerSecondGraphConsumer.java     |  13 --
 .../graph/impl/LatencyOverTimeGraphConsumer.java   |  13 --
 .../graph/impl/LatencyVSRequestGraphConsumer.java  |  12 --
 .../impl/ResponseCustomGraphGraphConsumer.java     |  13 --
 .../ResponseTimeDistributionGraphConsumer.java     |  18 --
 .../impl/ResponseTimeOverTimeGraphConsumer.java    |  13 --
 .../impl/ResponseTimePerSampleGraphConsumer.java   |  18 --
 .../impl/ResponseTimePercentilesGraphConsumer.java |  18 --
 .../impl/ResponseTimeVSRequestGraphConsumer.java   |  12 --
 ...heticResponseTimeDistributionGraphConsumer.java |  14 +-
 .../graph/impl/TimeVSThreadGraphConsumer.java      |  18 --
 .../graph/impl/TotalTPSGraphConsumer.java          |  13 --
 .../impl/TransactionsPerSecondGraphConsumer.java   |  13 --
 .../apache/jmeter/reporters/ResultCollector.java   |   2 +-
 .../org/apache/jmeter/reporters/ResultSaver.java   |   2 +-
 .../org/apache/jmeter/reporters/Summariser.java    |  19 +-
 .../apache/jmeter/samplers/AsynchSampleSender.java |   6 +-
 .../jmeter/samplers/DiskStoreSampleSender.java     |   4 +-
 .../jmeter/samplers/RemoteSampleListenerImpl.java  |   8 +-
 .../org/apache/jmeter/samplers/SampleResult.java   |   6 +-
 .../org/apache/jmeter/save/CSVSaveService.java     |  90 ++++-----
 .../java/org/apache/jmeter/save/SaveService.java   |   2 +-
 .../jmeter/save/converters/ConversionHelp.java     |   8 +-
 .../save/converters/SampleResultConverter.java     |  12 +-
 .../save/converters/TestElementConverter.java      |   2 +-
 .../java/org/apache/jmeter/swing/HtmlPane.java     |   2 +-
 .../testbeans/gui/BooleanPropertyEditor.java       |   8 +-
 .../jmeter/testbeans/gui/ComboStringEditor.java    |   8 +-
 .../apache/jmeter/testbeans/gui/EnumEditor.java    |  13 +-
 .../jmeter/testbeans/gui/FieldStringEditor.java    |   4 +-
 .../testbeans/gui/GenericTestBeanCustomizer.java   |  27 ++-
 .../testbeans/gui/IntegerPropertyEditor.java       |   4 +-
 .../jmeter/testbeans/gui/LongPropertyEditor.java   |   4 +-
 .../jmeter/testbeans/gui/PasswordEditor.java       |   4 +-
 .../apache/jmeter/testbeans/gui/TableEditor.java   |  14 +-
 .../apache/jmeter/testbeans/gui/TestBeanGUI.java   |   6 +-
 .../jmeter/testbeans/gui/TextAreaEditor.java       |   3 +-
 .../apache/jmeter/testbeans/gui/WrapperEditor.java |  10 +-
 .../jmeter/testelement/AbstractTestElement.java    |  14 +-
 .../org/apache/jmeter/testelement/TestPlan.java    |   4 +-
 .../testelement/property/BooleanProperty.java      |   4 +-
 .../testelement/property/CollectionProperty.java   |   4 +-
 .../testelement/property/FunctionProperty.java     |   4 +-
 .../jmeter/testelement/property/MapProperty.java   |   4 +-
 .../jmeter/testelement/property/MultiProperty.java |   4 +-
 .../testelement/property/NumberProperty.java       |   4 +-
 .../testelement/property/TestElementProperty.java  |   4 +-
 .../threads/FindTestElementsUpToRootTraverser.java |   4 +-
 .../org/apache/jmeter/threads/JMeterThread.java    |  34 ++--
 .../org/apache/jmeter/threads/JMeterVariables.java |   4 +-
 .../jmeter/threads/RemoteThreadsListenerImpl.java  |   3 -
 .../org/apache/jmeter/threads/TestCompiler.java    |   2 +-
 .../org/apache/jmeter/threads/ThreadGroup.java     |   2 +-
 .../apache/jmeter/threads/gui/ThreadGroupGui.java  |   4 +-
 .../org/apache/jmeter/timers/TimerService.java     |   2 +-
 .../apache/jmeter/util/BSFJavaScriptEngine.java    |  24 +--
 .../org/apache/jmeter/util/BSFTestElement.java     |   4 +-
 .../jmeter/util/BeanShellBeanInfoSupport.java      |  14 +-
 .../org/apache/jmeter/util/BeanShellServer.java    |   6 +-
 .../apache/jmeter/util/BeanShellTestElement.java   |   2 +-
 .../apache/jmeter/util/CustomX509TrustManager.java |  28 +--
 .../main/java/org/apache/jmeter/util/Document.java |   2 +-
 .../jmeter/util/HttpSSLProtocolSocketFactory.java  |   5 +-
 .../java/org/apache/jmeter/util/JMeterUtils.java   |   4 +-
 .../org/apache/jmeter/util/JSR223TestElement.java  |  13 +-
 .../org/apache/jmeter/util/JsseSSLManager.java     |   8 +-
 .../java/org/apache/jmeter/util/SSLManager.java    |   2 +-
 .../jmeter/util/ScriptingBeanInfoSupport.java      |  16 +-
 .../java/org/apache/jmeter/util/XPathUtil.java     |  58 +++---
 .../jmeter/util/keystore/JmeterKeyStore.java       |  11 +-
 .../java/org/apache/jmeter/visualizers/Sample.java |   4 +-
 .../org/apache/jmeter/visualizers/TableSample.java |   4 +-
 .../jmeter/visualizers/gui/AbstractVisualizer.java |   3 +-
 .../test/java/org/apache/jmeter/JMeterTest.java    |  86 +++++----
 .../jmeter/engine/DistributedRunnerTest.java       |   2 +-
 .../org/apache/jmeter/engine/LocalHostTest.java    |   6 +-
 .../jmeter/engine/util/TestValueReplacer.java      |   4 +-
 .../gui/logging/TestGuiLogEventAppender.java       |   4 +-
 .../processor/ErrorsSummaryConsumerTest.java       |   2 +-
 .../graph/impl/CustomGraphConsumerTest.java        |   2 +-
 .../samplers/TestDataStrippingSampleSender.java    |   2 +-
 .../apache/jmeter/samplers/TestSampleResult.java   |  10 +-
 .../org/apache/jmeter/save/TestCSVSaveService.java |   4 +-
 .../testbeans/gui/TestBooleanPropertyEditor.java   |   8 +-
 .../testbeans/gui/TestComboStringEditor.java       |   4 +-
 .../testbeans/gui/TestFieldStringEditor.java       |   4 +-
 .../jmeter/testelement/property/PackageTest.java   |   4 +-
 .../apache/jmeter/threads/TestJMeterThread.java    |   6 +-
 .../threads/TestUnmodifiableJMeterVariables.java   |   4 +-
 .../jmeter/util/SecurityProviderLoaderTest.java    |   2 +-
 .../org/apache/jmeter/junit/JMeterTestCase.java    |   4 +-
 .../org/apache/jmeter/resources/PackageTest.java   |  28 ++-
 .../jmeter/control/TestSwitchController.java       |  18 +-
 .../functions/ComponentReferenceFunctionTest.java  |  16 +-
 .../org/apache/jmeter/gui/action/TestLoad.java     |   4 +-
 .../java/org/apache/jmeter/junit/JMeterTest.java   |  26 +--
 .../org/apache/jmeter/save/TestSaveService.java    |   8 +-
 .../apache/jmeter/testelement/TestElementTest.java |   5 +-
 .../org/apache/jmeter/threads/ThreadGroupLoad.java |  83 ++++----
 .../apache/jorphan/reflect/TestClassFinder.java    |   2 +-
 src/dist/src/dist/expected_release_jars.csv        |   4 +-
 .../examples/sampler/gui/ExampleSamplerGui.java    |   2 +-
 .../testbeans/example3/Example3BeanInfo.java       |   8 +-
 .../jmeter/functions/AbstractHostIPName.java       |   8 +-
 .../org/apache/jmeter/functions/BeanShell.java     |   5 +-
 .../org/apache/jmeter/functions/FileToString.java  |   2 +-
 .../org/apache/jmeter/functions/FileWrapper.java   |   8 +-
 .../java/org/apache/jmeter/functions/Groovy.java   |   2 +-
 .../org/apache/jmeter/functions/IsVarDefined.java  |   2 +-
 .../apache/jmeter/functions/IterationCounter.java  |   2 +-
 .../org/apache/jmeter/functions/JavaScript.java    |   2 +-
 .../org/apache/jmeter/functions/Jexl2Function.java |   2 +-
 .../org/apache/jmeter/functions/Jexl3Function.java |   2 +-
 .../org/apache/jmeter/functions/LogFunction.java   |   6 +-
 .../org/apache/jmeter/functions/LogFunction2.java  |   2 +-
 .../java/org/apache/jmeter/functions/Property.java |   2 +-
 .../java/org/apache/jmeter/functions/Random.java   |   2 +-
 .../org/apache/jmeter/functions/RandomDate.java    |  12 +-
 .../org/apache/jmeter/functions/RandomString.java  |   2 +-
 .../org/apache/jmeter/functions/SamplerName.java   |   2 +-
 .../org/apache/jmeter/functions/SplitFunction.java |   2 +-
 .../org/apache/jmeter/functions/TimeShift.java     |   9 +-
 .../jmeter/functions/CSVReadFunctionTest.java      |   4 +-
 .../jmeter/functions/RandomFunctionTest.java       |   2 +-
 .../functions/StringFromFileFunctionTest.java      |   4 +-
 .../apache/jmeter/functions/SumFunctionTest.java   |   2 +-
 .../org/apache/jmeter/functions/Synchronizer.java  |   8 +-
 .../apache/jmeter/functions/TestStringtoFile.java  |   2 +-
 .../jmeter/functions/TestTimeShiftFunction.java    |   2 +-
 .../org/apache/commons/cli/avalon/CLOption.java    |   2 +-
 .../java/org/apache/jorphan/collections/Data.java  |   8 +-
 .../org/apache/jorphan/collections/HashTree.java   |   9 +-
 .../apache/jorphan/collections/ListedHashTree.java |   3 +-
 .../apache/jorphan/gui/AbstractTreeTableModel.java |   4 +-
 .../java/org/apache/jorphan/gui/DynamicStyle.java  |  18 +-
 .../java/org/apache/jorphan/gui/FocusActions.java  |   4 +-
 .../java/org/apache/jorphan/gui/MenuScroller.java  |   6 +-
 .../org/apache/jorphan/gui/MinMaxLongRenderer.java |   4 +-
 .../org/apache/jorphan/gui/ObjectTableSorter.java  |  11 +-
 .../java/org/apache/jorphan/gui/RateRenderer.java  |   5 +-
 .../apache/jorphan/gui/ui/KerningOptimizer.java    |   4 +-
 .../org/apache/jorphan/gui/ui/TextComponentUI.java |   4 +-
 .../main/java/org/apache/jorphan/io/TextFile.java  |   3 +-
 .../org/apache/jorphan/reflect/ClassFinder.java    |   5 +-
 .../java/org/apache/jorphan/util/BooleanUtils.java |  16 +-
 .../java/org/apache/jorphan/util/Converter.java    |   2 +-
 .../java/org/apache/jorphan/util/HeapDumper.java   |   8 +-
 .../java/org/apache/jorphan/util/StringWrap.java   |   4 +-
 .../java/org/apache/jorphan/util/XMLBuffer.java    |   2 +-
 .../apache/commons/cli/avalon/ClutilTestCase.java  |   2 +-
 .../org/apache/jorphan/exec/TestKeyToolUtils.java  |   2 +-
 .../apache/jorphan/gui/ObjectTableSorterTest.java  |   2 +-
 .../util/TestAlphaNumericKeyComparator.java        |   2 +-
 .../src/main/java/org/apache/jmeter/NewDriver.java |  12 +-
 .../bolt/config/BoltConnectionElementBeanInfo.java |   8 +-
 .../jmeter/protocol/bolt/sampler/BoltSampler.java  |   4 +-
 .../sampler/BoltTestElementBeanInfoSupport.java    |  14 +-
 .../jmeter/protocol/ftp/sampler/FTPSampler.java    |   6 +-
 .../protocol/http/config/gui/HttpDefaultsGui.java  |   1 +
 .../jmeter/protocol/http/control/CacheManager.java |  11 +-
 .../protocol/http/control/CookieManager.java       |   6 +-
 .../http/control/DelegatingKerberosScheme.java     |   4 +-
 .../http/control/DelegatingSPNegoScheme.java       |   4 +-
 .../http/control/DynamicKerberosSchemeFactory.java |   4 +-
 .../http/control/DynamicSPNegoSchemeFactory.java   |   4 +-
 .../protocol/http/control/HeaderManager.java       |   3 +-
 .../protocol/http/control/HttpMirrorServer.java    |   2 +-
 .../protocol/http/control/KerberosManager.java     |   6 +-
 .../http/control/gui/HttpMirrorControlGui.java     |   4 +-
 .../http/control/gui/HttpTestSampleGui.java        |   1 +
 .../jmeter/protocol/http/curl/BasicCurlParser.java |  71 ++++---
 .../apache/jmeter/protocol/http/gui/AuthPanel.java |  70 +++----
 .../jmeter/protocol/http/gui/CookiePanel.java      |   3 +-
 .../jmeter/protocol/http/gui/DNSCachePanel.java    |   3 +-
 .../protocol/http/gui/HTTPArgumentsPanel.java      |   6 +-
 .../protocol/http/gui/HTTPFileArgsPanel.java       |   6 +-
 .../jmeter/protocol/http/gui/HeaderPanel.java      |   8 +-
 .../http/gui/action/ParseCurlCommandAction.java    |  24 +--
 .../protocol/http/modifier/AnchorModifier.java     |   6 +-
 .../http/modifier/RegExUserParameters.java         |   3 +-
 .../http/modifier/URLRewritingModifier.java        |   4 +-
 .../http/modifier/gui/RegExUserParametersGui.java  |   6 +-
 .../jmeter/protocol/http/parser/BaseParser.java    |   4 +-
 .../protocol/http/parser/JTidyHTMLParser.java      | 183 +++++++++---------
 .../protocol/http/parser/JsoupBasedHtmlParser.java |   7 +-
 .../http/parser/LagartoBasedHtmlParser.java        | 140 +++++++-------
 .../jmeter/protocol/http/parser/URLCollection.java |   4 +-
 .../http/proxy/AbstractSamplerCreator.java         |   4 +-
 .../protocol/http/proxy/DefaultSamplerCreator.java |  15 +-
 .../jmeter/protocol/http/proxy/HttpReplyHdr.java   |   2 +-
 .../jmeter/protocol/http/proxy/HttpRequestHdr.java |   2 +-
 .../apache/jmeter/protocol/http/proxy/Proxy.java   |  49 +++--
 .../jmeter/protocol/http/proxy/ProxyControl.java   |  74 ++++----
 .../protocol/http/proxy/gui/ProxyControlGui.java   |  17 +-
 .../protocol/http/proxy/gui/RecorderDialog.java    |   6 +-
 .../protocol/http/sampler/AccessLogSampler.java    |   8 +-
 .../http/sampler/AccessLogSamplerBeanInfo.java     |  26 +--
 .../protocol/http/sampler/HTTPAbstractImpl.java    |  36 ++--
 .../jmeter/protocol/http/sampler/HTTPFileImpl.java |   2 +-
 .../jmeter/protocol/http/sampler/HTTPHC4Impl.java  |  34 ++--
 .../protocol/http/sampler/HTTPHCAbstractImpl.java  |   8 +-
 .../jmeter/protocol/http/sampler/HTTPJavaImpl.java |  10 +-
 .../protocol/http/sampler/HTTPSampleResult.java    |   5 +-
 .../protocol/http/sampler/HTTPSamplerBase.java     |  37 ++--
 .../protocol/http/sampler/HTTPSamplerProxy.java    |   3 -
 .../http/sampler/HttpClientDefaultParameters.java  |   4 +-
 .../jmeter/protocol/http/sampler/PutWriter.java    |   4 +-
 .../protocol/http/sampler/ResourcesDownloader.java |   3 +-
 .../http/sampler/hc/LaxDeflateInputStream.java     |   3 -
 .../http/sampler/hc/LaxGZIPInputStream.java        |   3 -
 .../jmeter/protocol/http/util/ConversionUtils.java |   2 +-
 .../http/util/GraphQLRequestParamUtils.java        |   4 +-
 .../jmeter/protocol/http/util/HTTPFileArg.java     |   6 +-
 .../protocol/http/util/HTTPResultConverter.java    |   6 +-
 .../http/util/accesslog/SessionFilter.java         |   5 -
 .../http/util/accesslog/SharedTCLogParser.java     |   2 +-
 .../protocol/http/util/accesslog/TCLogParser.java  |   2 +-
 .../protocol/http/visualizers/RequestViewHTTP.java |  21 +--
 .../gui/action/ParseCurlCommandActionTest.java     |  10 +-
 .../http/config/MultipartUrlConfigTest.java        | 104 ++++++-----
 .../http/control/TestCacheManagerBase.java         |   2 +-
 .../protocol/http/control/TestCacheManagerHC4.java |  15 --
 .../control/TestCacheManagerThreadIteration.java   |  28 ---
 .../control/TestCacheManagerUrlConnection.java     |   2 +-
 .../http/control/TestHTTPMirrorThread.java         |   4 +-
 .../protocol/http/modifier/TestAnchorModifier.java |   4 +-
 .../http/modifier/TestURLRewritingModifier.java    |   2 +-
 .../jmeter/protocol/http/parser/TestCssParser.java |   2 +-
 .../protocol/http/parser/TestHTMLParser.java       |   6 +-
 .../protocol/http/proxy/TestHttpRequestHdr.java    |  24 +--
 .../jmeter/protocol/http/sampler/HTTPSampler3.java |   3 -
 .../jmeter/protocol/http/sampler/PackageTest.java  |   2 +-
 .../http/sampler/ParallelResourcesAndIpSource.java |  44 ++---
 .../protocol/http/sampler/PostWriterTest.java      |  42 ++---
 .../protocol/http/sampler/SamplingNamingTest.java  |   2 +-
 .../protocol/http/sampler/TestDecompression.java   |   2 +-
 .../TestHTTPSamplersAgainstHttpMirrorServer.java   | 123 ++++++------
 .../protocol/http/sampler/TestRedirects.java       |   2 +-
 .../protocol/http/util/TestHTTPFileArgs.java       |   7 +-
 .../http/visualizers/RequestViewHTTPTest.java      |  57 +++---
 .../protocol/java/config/gui/JavaConfigGui.java    |   3 -
 .../java/control/gui/JavaTestSamplerGui.java       |   3 -
 .../jmeter/protocol/java/sampler/BSFSampler.java   |   2 +-
 .../jmeter/protocol/java/sampler/JavaSampler.java  |   8 +-
 .../protocol/java/sampler/JavaSamplerContext.java  |   4 +-
 .../apache/jmeter/protocol/java/test/JavaTest.java |   4 +-
 .../protocol/jdbc/AbstractJDBCTestElement.java     |  96 +++-------
 .../jdbc/JDBCTestElementBeanInfoSupport.java       |  24 +--
 .../protocol/jdbc/config/DataSourceElement.java    |  14 +-
 .../jdbc/config/DataSourceElementBeanInfo.java     |  44 ++---
 .../java/org/apache/jmeter/protocol/jms/Utils.java |  10 +-
 .../protocol/jms/client/InitialContextFactory.java |   2 +-
 .../protocol/jms/client/ReceiveSubscriber.java     |   2 +-
 .../jms/control/gui/JMSPropertiesPanel.java        |  64 +++----
 .../protocol/jms/control/gui/JMSSamplerGui.java    |   6 +-
 .../protocol/jms/sampler/BaseJMSSampler.java       |   4 +-
 .../jmeter/protocol/jms/sampler/JMSSampler.java    |   7 +-
 .../jmeter/protocol/jms/sampler/MessageAdmin.java  |   6 +-
 .../protocol/jms/sampler/PublisherSampler.java     |  31 ++-
 .../protocol/jms/sampler/SubscriberSampler.java    |  13 +-
 .../protocol/jms/sampler/render/FileKey.java       |   4 +-
 .../jms/sampler/render/ObjectMessageRenderer.java  |   2 +-
 .../sampler/render/BinaryMessageRendererTest.java  |   2 +-
 .../sampler/render/ObjectMessageRendererTest.java  |   4 +-
 .../src/main/java/test/DummyAnnotatedTest.java     |  14 +-
 .../java/control/gui/JUnitTestSamplerGui.java      |  14 +-
 .../jmeter/protocol/java/sampler/JUnitSampler.java |  18 +-
 .../ldap/config/gui/LDAPArgumentsPanel.java        |   7 +-
 .../protocol/ldap/config/gui/LdapExtConfigGui.java |   2 +-
 .../protocol/ldap/sampler/LDAPExtSampler.java      |  26 +--
 .../protocol/ldap/sampler/LdapExtClient.java       |   4 +-
 .../protocol/mail/sampler/MailReaderSampler.java   |  22 +--
 .../mail/sampler/gui/MailReaderSamplerGui.java     |   2 +-
 .../jmeter/protocol/smtp/sampler/SmtpSampler.java  |   6 +-
 .../protocol/smtp/sampler/gui/SmtpPanel.java       |  25 +--
 .../protocol/smtp/sampler/gui/SmtpSamplerGui.java  |   4 +-
 .../smtp/sampler/protocol/SendMailCommand.java     |  10 +-
 .../mongodb/config/MongoSourceElement.java         |   4 +-
 .../mongodb/config/MongoSourceElementBeanInfo.java |  44 ++---
 .../protocol/mongodb/mongo/EvalResultHandler.java  |  16 +-
 .../mongodb/sampler/MongoScriptSampler.java        |   3 -
 .../sampler/MongoScriptSamplerBeanInfo.java        |  12 +-
 .../jmeter/protocol/tcp/sampler/TCPSampler.java    |   8 +-
 xdocs/extending/notes_on_extending.txt             |  10 +-
 xdocs/usermanual/jmeter_tutorial.xml               |   8 +-
 496 files changed, 2263 insertions(+), 3748 deletions(-)

diff --git a/src/bshclient/src/main/java/org/apache/jmeter/util/BeanShellClient.java b/src/bshclient/src/main/java/org/apache/jmeter/util/BeanShellClient.java
index 207009bd90..12b8928f35 100644
--- a/src/bshclient/src/main/java/org/apache/jmeter/util/BeanShellClient.java
+++ b/src/bshclient/src/main/java/org/apache/jmeter/util/BeanShellClient.java
@@ -90,7 +90,7 @@ public class BeanShellClient {
 
         private final InputStream is;
 
-        public SockRead(InputStream _is) {
+        private SockRead(InputStream _is) {
             this.is=_is;
         }
 
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/CompareAssertionBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/assertions/CompareAssertionBeanInfo.java
index 1e38d9c501..401e9cb2c2 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/CompareAssertionBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/CompareAssertionBeanInfo.java
@@ -31,13 +31,13 @@ public class CompareAssertionBeanInfo extends BeanInfoSupport {
         createPropertyGroup("compareChoices", new String[] { "compareContent", "compareTime" }); //$NON-NLS-1$ $NON-NLS-2$ $NON-NLS-3$
         createPropertyGroup("comparison_filters", new String[]{"stringsToSkip"}); //$NON-NLS-1$ $NON-NLS-2$
         PropertyDescriptor p = property("compareContent"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(DEFAULT, true);
+        p.setValue(NOT_EXPRESSION, true);
         p = property("compareTime"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, -1L);
-        p.setValue(NOT_EXPRESSION, Boolean.FALSE);
+        p.setValue(NOT_EXPRESSION, false);
         p = property("stringsToSkip"); //$NON-NLS-1$
         p.setPropertyEditorClass(TableEditor.class);
         p.setValue(TableEditor.CLASSNAME,SubstitutionElement.class.getName());
@@ -46,9 +46,9 @@ public class CompareAssertionBeanInfo extends BeanInfoSupport {
                 JMeterUtils.getResString("comparison_regex_substitution")}); //$NON-NLS-1$
         p.setValue(TableEditor.OBJECT_PROPERTIES, // These are the names of the get/set methods
                 new String[]{SubstitutionElement.REGEX, SubstitutionElement.SUBSTITUTE});
-        p.setValue(NOT_UNDEFINED,Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED,true);
         p.setValue(DEFAULT, new ArrayList<>());
-        p.setValue(MULTILINE,Boolean.TRUE);
+        p.setValue(MULTILINE,true);
 
     }
 
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/HTMLAssertion.java b/src/components/src/main/java/org/apache/jmeter/assertions/HTMLAssertion.java
index b1bcc91381..0c17f023a5 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/HTMLAssertion.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/HTMLAssertion.java
@@ -100,9 +100,7 @@ public class HTMLAssertion extends AbstractTestElement implements Serializable,
             return result;
         }
 
-        /*
-         * Run tidy.
-         */
+        // Run tidy.
         try {
             log.debug("HTMLAssertions.getResult(): start parsing with tidy ...");
 
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/JSONPathAssertion.java b/src/components/src/main/java/org/apache/jmeter/assertions/JSONPathAssertion.java
index 3e15e915dd..975a6c7658 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/JSONPathAssertion.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/JSONPathAssertion.java
@@ -117,8 +117,7 @@ public class JSONPathAssertion extends AbstractTestElement implements Serializab
         Object value = JsonPath.read(jsonString, getJsonPath());
 
         if (!isJsonValidationBool()) {
-            if (value instanceof JSONArray) {
-                JSONArray arrayValue = (JSONArray) value;
+            if (value instanceof JSONArray arrayValue) {
                 if (arrayValue.isEmpty() && !JsonPath.isPathDefinite(getJsonPath())) {
                     throw new IllegalStateException(String.format("JSONPath '%s' is indefinite and the extracted Value is an empty Array." +
                             " Please use an assertion value, to be sure to get a correct result. Expected value was '%s'", getJsonPath(), getExpectedValue()));
@@ -127,8 +126,8 @@ public class JSONPathAssertion extends AbstractTestElement implements Serializab
             return;
         }
 
-        if (value instanceof JSONArray) {
-            if (arrayMatched((JSONArray) value)) {
+        if (value instanceof JSONArray objects) {
+            if (arrayMatched(objects)) {
                 return;
             }
         } else {
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/ResponseAssertion.java b/src/components/src/main/java/org/apache/jmeter/assertions/ResponseAssertion.java
index 24e7673045..f7df66aaa2 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/ResponseAssertion.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/ResponseAssertion.java
@@ -463,30 +463,16 @@ public class ResponseAssertion extends AbstractScopedAssertion implements Serial
             sb.append("URL");
         }
 
-        switch (getTestType()) {
-        case CONTAINS:
-        case SUBSTRING:
-            sb.append(" expected to contain ");
-            break;
-        case NOT | CONTAINS:
-        case NOT | SUBSTRING:
-            sb.append(" expected not to contain ");
-            break;
-        case MATCH:
-            sb.append(" expected to match ");
-            break;
-        case NOT | MATCH:
-            sb.append(" expected not to match ");
-            break;
-        case EQUALS:
-            sb.append(" expected to equal ");
-            break;
-        case NOT | EQUALS:
-            sb.append(" expected not to equal ");
-            break;
-        default:// should never happen...
-            sb.append(" expected something using ");
-        }
+        sb.append(switch (getTestType()) {
+            case CONTAINS, SUBSTRING -> " expected to contain ";
+            case NOT | CONTAINS, NOT | SUBSTRING -> " expected not to contain ";
+            case MATCH -> " expected to match ";
+            case NOT | MATCH -> " expected not to match ";
+            case EQUALS -> " expected to equal ";
+            case NOT | EQUALS -> " expected not to equal ";
+            default ->// should never happen...
+                    " expected something using ";
+        });
 
         sb.append("/");
 
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/SMIMEAssertion.java b/src/components/src/main/java/org/apache/jmeter/assertions/SMIMEAssertion.java
index 5c08bbbe20..4c9471c5dc 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/SMIMEAssertion.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/SMIMEAssertion.java
@@ -175,7 +175,7 @@ class SMIMEAssertion {
                         checkSubject(testElement, res, cert, failureMessage);
                         checkIssuer(testElement, res, cert, failureMessage);
 
-                        if (failureMessage.length() > 0) {
+                        if (!failureMessage.isEmpty()) {
                             res.setFailureMessage(failureMessage.toString());
                         }
                     }
@@ -244,7 +244,7 @@ class SMIMEAssertion {
     private static void checkIssuer(SMIMEAssertionTestElement testElement, AssertionResult res,
             X509CertificateHolder cert, StringBuilder failureMessage) {
         String issuer = testElement.getIssuerDn();
-        if (issuer.length() > 0) {
+        if (!issuer.isEmpty()) {
             String subject = testElement.getSignerDn();
             final X500Name issuerX500Name = cert.getIssuer();
             log.debug("IssuerDN from cert: {}", issuerX500Name);
@@ -262,7 +262,7 @@ class SMIMEAssertion {
     private static void checkSubject(SMIMEAssertionTestElement testElement, AssertionResult res,
             X509CertificateHolder cert, StringBuilder failureMessage) {
         String subject = testElement.getSignerDn();
-        if (subject.length() > 0) {
+        if (!subject.isEmpty()) {
             final X500Name certPrincipal = cert.getSubject();
             log.debug("DN from cert: {}", certPrincipal);
             X500Name principal = new X500Name(subject);
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/SizeAssertion.java b/src/components/src/main/java/org/apache/jmeter/assertions/SizeAssertion.java
index ac2ad0132b..7b3e1ad5d2 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/SizeAssertion.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/SizeAssertion.java
@@ -74,21 +74,14 @@ public class SizeAssertion extends AbstractScopedAssertion implements Serializab
         }
 
         public boolean evaluate(long actual, long expected) {
-            switch (this) {
-                case EQUAL:
-                    return actual == expected;
-                case NOTEQUAL:
-                    return actual != expected;
-                case GREATERTHAN:
-                    return actual > expected;
-                case LESSTHAN:
-                    return actual < expected;
-                case GREATERTHANEQUAL:
-                    return actual >= expected;
-                case LESSTHANEQUAL:
-                    return actual <= expected;
-            }
-            throw new IllegalStateException("Unexpected value: " + this);
+            return switch (this) {
+                case EQUAL -> actual == expected;
+                case NOTEQUAL -> actual != expected;
+                case GREATERTHAN -> actual > expected;
+                case LESSTHAN -> actual < expected;
+                case GREATERTHANEQUAL -> actual >= expected;
+                case LESSTHANEQUAL -> actual <= expected;
+            };
         }
     }
 
@@ -166,7 +159,7 @@ public class SizeAssertion extends AbstractScopedAssertion implements Serializab
         }
         // is the Sample the correct size?
         final String msg = compareSize(resultSize);
-        if (msg.length() > 0) {
+        if (!msg.isEmpty()) {
             result.setFailure(true);
             Object[] arguments = {resultSize, msg, Long.valueOf(getAllowedSize()) };
             String message = MessageFormat.format(
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/XMLAssertion.java b/src/components/src/main/java/org/apache/jmeter/assertions/XMLAssertion.java
index 6aa6d113ae..468603a22d 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/XMLAssertion.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/XMLAssertion.java
@@ -70,7 +70,7 @@ public class XMLAssertion extends AbstractTestElement implements Serializable, A
         // no error as default
         AssertionResult result = new AssertionResult(getName());
         String resultData = response.getResponseDataAsString();
-        if (resultData.length() == 0) {
+        if (resultData.isEmpty()) {
             return result.setResultForNull();
         }
         result.setFailure(false);
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/XMLSchemaAssertion.java b/src/components/src/main/java/org/apache/jmeter/assertions/XMLSchemaAssertion.java
index 204675821b..ed3b5544e3 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/XMLSchemaAssertion.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/XMLSchemaAssertion.java
@@ -59,7 +59,7 @@ public class XMLSchemaAssertion extends AbstractTestElement implements Serializa
         // Note: initialised with error = failure = false
 
         String resultData = response.getResponseDataAsString();
-        if (resultData.length() == 0) {
+        if (resultData.isEmpty()) {
             return result.setResultForNull();
         }
 
@@ -141,16 +141,13 @@ public class XMLSchemaAssertion extends AbstractTestElement implements Serializa
     private static class SAXErrorHandler implements ErrorHandler {
         private final AssertionResult result;
 
-        public SAXErrorHandler(AssertionResult result) {
+        private SAXErrorHandler(AssertionResult result) {
             this.result = result;
         }
 
-        /*
-         * Can be caused by: - failure to read XSD file - xml does not match XSD
-         */
         @Override
         public void error(SAXParseException exception) throws SAXParseException {
-
+            // Can be caused by: - failure to read XSD file - xml does not match XSD
             String msg = "error: " + errorDetails(exception);
             log.debug(msg);
             result.setFailureMessage(msg);
@@ -158,12 +155,9 @@ public class XMLSchemaAssertion extends AbstractTestElement implements Serializa
             throw exception;
         }
 
-        /*
-         * Can be caused by: - premature end of file - non-whitespace content
-         * after trailer
-         */
         @Override
         public void fatalError(SAXParseException exception) throws SAXParseException {
+            // Can be caused by: - premature end of file - non-whitespace content after trailer
             String msg = "fatal: " + errorDetails(exception);
             log.debug(msg);
             result.setFailureMessage(msg);
@@ -171,11 +165,9 @@ public class XMLSchemaAssertion extends AbstractTestElement implements Serializa
             throw exception;
         }
 
-        /*
-         * Not clear what can cause this ? conflicting versions perhaps
-         */
         @Override
         public void warning(SAXParseException exception) throws SAXParseException {
+            // Not clear what can cause this ? conflicting versions perhaps
             String msg = "warning: " + errorDetails(exception);
             log.debug(msg);
             result.setFailureMessage(msg);
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/gui/AssertionGui.java b/src/components/src/main/java/org/apache/jmeter/assertions/gui/AssertionGui.java
index c4b252c020..bc9262276a 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/gui/AssertionGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/gui/AssertionGui.java
@@ -157,8 +157,7 @@ public class AssertionGui extends AbstractAssertionGui {
     public void modifyTestElement(TestElement el) {
         GuiUtils.stopTableEditing(stringTable);
         configureTestElement(el);
-        if (el instanceof ResponseAssertion) {
-            ResponseAssertion ra = (ResponseAssertion) el;
+        if (el instanceof ResponseAssertion ra) {
             ra.setCustomFailureMessage(alternativeFailureMessage.getText());
             saveScopeSettings(ra);
 
@@ -294,7 +293,7 @@ public class AssertionGui extends AbstractAssertionGui {
             tableModel.addRow(new Object[] { jMeterProperty.getStringValue() });
         }
 
-        boolean testStringsPresent = model.getTestStrings().size() != 0;
+        boolean testStringsPresent = !model.getTestStrings().isEmpty();
         deletePattern.setEnabled(testStringsPresent);
 
         tableModel.fireTableDataChanged();
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/gui/DurationAssertionGui.java b/src/components/src/main/java/org/apache/jmeter/assertions/gui/DurationAssertionGui.java
index 93d3f87677..0aeb065116 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/gui/DurationAssertionGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/gui/DurationAssertionGui.java
@@ -68,8 +68,7 @@ public class DurationAssertionGui extends AbstractAssertionGui {
     @Override
     public void modifyTestElement(TestElement el) {
         configureTestElement(el);
-        if (el instanceof DurationAssertion) {
-            DurationAssertion assertion = (DurationAssertion) el;
+        if (el instanceof DurationAssertion assertion) {
             assertion.setProperty(DurationAssertion.DURATION_KEY,duration.getText());
             saveScopeSettings(assertion);
         }
@@ -88,8 +87,7 @@ public class DurationAssertionGui extends AbstractAssertionGui {
     @Override
     public void configure(TestElement el) {
         super.configure(el);
-        if (el instanceof DurationAssertion){
-            DurationAssertion da = (DurationAssertion) el;
+        if (el instanceof DurationAssertion da){
             duration.setText(da.getPropertyAsString(DurationAssertion.DURATION_KEY));
             showScopeSettings(da);
         }
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/gui/JSONPathAssertionGui.java b/src/components/src/main/java/org/apache/jmeter/assertions/gui/JSONPathAssertionGui.java
index d482c7530b..44c4857cc8 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/gui/JSONPathAssertionGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/gui/JSONPathAssertionGui.java
@@ -130,8 +130,7 @@ public class JSONPathAssertionGui extends AbstractAssertionGui implements Change
     @Override
     public void modifyTestElement(TestElement element) {
         super.configureTestElement(element);
-        if (element instanceof JSONPathAssertion) {
-            JSONPathAssertion jpAssertion = (JSONPathAssertion) element;
+        if (element instanceof JSONPathAssertion jpAssertion) {
             jpAssertion.setJsonPath(jsonPath.getText());
             jpAssertion.setExpectedValue(jsonValue.getText());
             jpAssertion.setJsonValidationBool(jsonValidation.isSelected());
@@ -144,8 +143,7 @@ public class JSONPathAssertionGui extends AbstractAssertionGui implements Change
     @Override
     public void configure(TestElement element) {
         super.configure(element);
-        if (element instanceof JSONPathAssertion) {
-            JSONPathAssertion jpAssertion = (JSONPathAssertion) element;
+        if (element instanceof JSONPathAssertion jpAssertion) {
             jsonPath.setText(jpAssertion.getJsonPath());
             jsonValue.setText(jpAssertion.getExpectedValue());
             jsonValidation.setSelected(jpAssertion.isJsonValidationBool());
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/gui/MD5HexAssertionGUI.java b/src/components/src/main/java/org/apache/jmeter/assertions/gui/MD5HexAssertionGUI.java
index 700fb51c86..a0f65e7f55 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/gui/MD5HexAssertionGUI.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/gui/MD5HexAssertionGUI.java
@@ -81,9 +81,6 @@ public class MD5HexAssertionGUI extends AbstractAssertionGui {
         return "md5hex_assertion_title"; // $NON-NLS-1$
     }
 
-    /*
-     * @return
-     */
     @Override
     public TestElement createTestElement() {
 
@@ -93,9 +90,6 @@ public class MD5HexAssertionGUI extends AbstractAssertionGui {
 
     }
 
-    /*
-     * @param element
-     */
     @Override
     public void modifyTestElement(TestElement element) {
         configureTestElement(element);
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/gui/XPath2AssertionGui.java b/src/components/src/main/java/org/apache/jmeter/assertions/gui/XPath2AssertionGui.java
index 5f5e50a10b..de16e1ccc8 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/gui/XPath2AssertionGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/gui/XPath2AssertionGui.java
@@ -101,8 +101,7 @@ public class XPath2AssertionGui extends AbstractAssertionGui { // $NOSONAR
     @Override
     public void modifyTestElement(TestElement el) {
         super.configureTestElement(el);
-        if (el instanceof XPath2Assertion) {
-            XPath2Assertion assertion = (XPath2Assertion) el;
+        if (el instanceof XPath2Assertion assertion) {
             saveScopeSettings(assertion);
             assertion.setNegated(xpath.isNegated());
             assertion.setXPathString(xpath.getXPath());
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/gui/XPathAssertionGui.java b/src/components/src/main/java/org/apache/jmeter/assertions/gui/XPathAssertionGui.java
index 757e78fd57..ae8d813e13 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/gui/XPathAssertionGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/gui/XPathAssertionGui.java
@@ -109,8 +109,7 @@ public class XPathAssertionGui extends AbstractAssertionGui {
     @Override
     public void modifyTestElement(TestElement el) {
         super.configureTestElement(el);
-        if (el instanceof XPathAssertion) {
-            XPathAssertion assertion = (XPathAssertion) el;
+        if (el instanceof XPathAssertion assertion) {
             saveScopeSettings(assertion);
             assertion.setNegated(xpath.isNegated());
             assertion.setXPathString(xpath.getXPath());
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/jmespath/JMESPathAssertion.java b/src/components/src/main/java/org/apache/jmeter/assertions/jmespath/JMESPathAssertion.java
index c6b615dd65..74668c66d5 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/jmespath/JMESPathAssertion.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/jmespath/JMESPathAssertion.java
@@ -224,9 +224,6 @@ public class JMESPathAssertion extends AbstractTestElement implements Serializab
         JMESPathCache.getInstance().cleanUp();
     }
 
-    /*
-     * ------------------------ GETTER/SETTER ------------------------
-     */
     public String getJmesPath() {
         return getPropertyAsString(JMESPATH);
     }
diff --git a/src/components/src/main/java/org/apache/jmeter/assertions/jmespath/gui/JMESPathAssertionGui.java b/src/components/src/main/java/org/apache/jmeter/assertions/jmespath/gui/JMESPathAssertionGui.java
index af8e52046e..5108eb01ee 100644
--- a/src/components/src/main/java/org/apache/jmeter/assertions/jmespath/gui/JMESPathAssertionGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/assertions/jmespath/gui/JMESPathAssertionGui.java
@@ -113,8 +113,7 @@ public class JMESPathAssertionGui extends JSONPathAssertionGui {
     @Override
     public void modifyTestElement(TestElement element) {
         super.configureTestElement(element);
-        if (element instanceof JMESPathAssertion) {
-            JMESPathAssertion jmesAssertion = (JMESPathAssertion) element;
+        if (element instanceof JMESPathAssertion jmesAssertion) {
             jmesAssertion.setJmesPath(jsonPath.getText());
             jmesAssertion.setExpectedValue(jsonValue.getText());
             jmesAssertion.setJsonValidationBool(jsonValidation.isSelected());
@@ -130,8 +129,7 @@ public class JMESPathAssertionGui extends JSONPathAssertionGui {
     @Override
     public void configure(TestElement element) {
         super.configure(element);
-        if (element instanceof JMESPathAssertion) {
-            JMESPathAssertion jmesAssertion = (JMESPathAssertion) element;
+        if (element instanceof JMESPathAssertion jmesAssertion) {
             jsonPath.setText(jmesAssertion.getJmesPath());
             jsonValue.setText(jmesAssertion.getExpectedValue());
             jsonValidation.setSelected(jmesAssertion.isJsonValidationBool());
diff --git a/src/components/src/main/java/org/apache/jmeter/config/CSVDataSet.java b/src/components/src/main/java/org/apache/jmeter/config/CSVDataSet.java
index 7e0f66068d..ee3bf0f010 100644
--- a/src/components/src/main/java/org/apache/jmeter/config/CSVDataSet.java
+++ b/src/components/src/main/java/org/apache/jmeter/config/CSVDataSet.java
@@ -121,7 +121,7 @@ public class CSVDataSet extends ConfigTestElement
      */
     @Override
     public void setProperty(JMeterProperty property) {
-        if (!(property instanceof StringProperty)) {
+        if (!(property instanceof StringProperty stringProperty)) {
             super.setProperty(property);
             return;
         }
@@ -142,7 +142,7 @@ public class CSVDataSet extends ConfigTestElement
                         if (log.isDebugEnabled()) {
                             log.debug("Converted {}={} to {} using Locale: {}", propName, propValue, resKey, rb.getLocale());
                         }
-                        ((StringProperty) property).setValue(resKey); // reset the value
+                        stringProperty.setValue(resKey); // reset the value
                         super.setProperty(property);
                         return;
                     }
diff --git a/src/components/src/main/java/org/apache/jmeter/config/CSVDataSetBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/config/CSVDataSetBeanInfo.java
index 2d3f5aeab0..5393963da7 100644
--- a/src/components/src/main/java/org/apache/jmeter/config/CSVDataSetBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/config/CSVDataSetBeanInfo.java
@@ -61,48 +61,48 @@ public class CSVDataSetBeanInfo extends BeanInfoSupport {
                         RECYCLE, STOPTHREAD, SHAREMODE });
 
         PropertyDescriptor p = property(FILENAME);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "");        //$NON-NLS-1$
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
+        p.setValue(NOT_EXPRESSION, true);
         p.setPropertyEditorClass(FileEditor.class);
 
         p = property(FILE_ENCODING, TypeEditor.ComboStringEditor);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "");        //$NON-NLS-1$
         p.setValue(TAGS, getListFileEncoding());
 
         p = property(VARIABLE_NAMES);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "");        //$NON-NLS-1$
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
+        p.setValue(NOT_EXPRESSION, true);
 
         p = property(IGNORE_FIRST_LINE);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(DEFAULT, false);
 
         p = property(DELIMITER);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, ",");        //$NON-NLS-1$
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
+        p.setValue(NOT_EXPRESSION, true);
 
         p = property(QUOTED_DATA);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(DEFAULT, false);
 
         p = property(RECYCLE);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(DEFAULT, true);
 
         p = property(STOPTHREAD);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(DEFAULT, false);
 
         p = property(SHAREMODE, TypeEditor.ComboStringEditor);
         p.setValue(RESOURCE_BUNDLE, getBeanDescriptor().getValue(RESOURCE_BUNDLE));
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, SHARE_TAGS[SHARE_ALL]);
-        p.setValue(NOT_OTHER, Boolean.FALSE);
-        p.setValue(NOT_EXPRESSION, Boolean.FALSE);
+        p.setValue(NOT_OTHER, false);
+        p.setValue(NOT_EXPRESSION, false);
         p.setValue(TAGS, SHARE_TAGS);
     }
 
diff --git a/src/components/src/main/java/org/apache/jmeter/config/KeystoreConfigBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/config/KeystoreConfigBeanInfo.java
index 32a5a6fd25..271d54e9ed 100644
--- a/src/components/src/main/java/org/apache/jmeter/config/KeystoreConfigBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/config/KeystoreConfigBeanInfo.java
@@ -43,22 +43,22 @@ public class KeystoreConfigBeanInfo extends BeanInfoSupport {
                 PRELOAD, CLIENT_CERT_ALIAS_VAR_NAME, ALIAS_START_INDEX, ALIAS_END_INDEX });
 
         PropertyDescriptor p = property(PRELOAD);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "True"); // $NON-NLS-1$
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
         p.setValue(TAGS, new String[]{"True", "False"}); // $NON-NLS-1$ $NON-NLS-2$
 
         p = property(CLIENT_CERT_ALIAS_VAR_NAME);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, JmeterKeyStore.DEFAULT_ALIAS_VAR_NAME); // $NON-NLS-1$
 
         p = property(ALIAS_START_INDEX);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "0"); // $NON-NLS-1$
 
         p = property(ALIAS_END_INDEX);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "-1"); // $NON-NLS-1$
     }
 }
diff --git a/src/components/src/main/java/org/apache/jmeter/config/RandomVariableConfig.java b/src/components/src/main/java/org/apache/jmeter/config/RandomVariableConfig.java
index 0f81571dde..43661d11cb 100644
--- a/src/components/src/main/java/org/apache/jmeter/config/RandomVariableConfig.java
+++ b/src/components/src/main/java/org/apache/jmeter/config/RandomVariableConfig.java
@@ -41,10 +41,8 @@ public class RandomVariableConfig extends ConfigTestElement
 
     private static final long serialVersionUID = 235L;
 
-    /*
-     *  N.B. this class is shared between threads (NoThreadClone) so all access to variables
-     *  needs to be protected by a lock (either sync. or volatile) to ensure safe publication.
-     */
+    // N.B. this class is shared between threads (NoThreadClone) so all access to variables
+    // needs to be protected by a lock (either sync. or volatile) to ensure safe publication.
 
     private String minimumValue;
 
@@ -81,7 +79,7 @@ public class RandomVariableConfig extends ConfigTestElement
         return this;
     }
 
-    /*
+    /**
      * nextInt(n) returns values in the range [0,n),
      * so n must be set to max-min+1
      */
@@ -207,7 +205,7 @@ public class RandomVariableConfig extends ConfigTestElement
     }
 
     private Random createRandom() {
-        if (randomSeed.length()>0){
+        if (!randomSeed.isEmpty()){
             Long seed = getRandomSeedAsLong();
             if(seed != null) {
                 return new Random(seed);
diff --git a/src/components/src/main/java/org/apache/jmeter/config/RandomVariableConfigBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/config/RandomVariableConfigBeanInfo.java
index d09e2b9d0f..b1b508a5ee 100644
--- a/src/components/src/main/java/org/apache/jmeter/config/RandomVariableConfigBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/config/RandomVariableConfigBeanInfo.java
@@ -44,34 +44,34 @@ public class RandomVariableConfigBeanInfo extends BeanInfoSupport {
         createPropertyGroup(VARIABLE_GROUP, new String[] { VARIABLE_NAME, OUTPUT_FORMAT, });
 
         p = property(VARIABLE_NAME);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, ""); // $NON-NLS-1$
 
         p = property(OUTPUT_FORMAT);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, ""); // $NON-NLS-1$
 
         createPropertyGroup(RANDOM_GROUP,
         new String[] { MINIMUM_VALUE, MAXIMUM_VALUE, RANDOM_SEED, });
 
         p = property(MINIMUM_VALUE);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "1"); // $NON-NLS-1$
 
         p = property(MAXIMUM_VALUE);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, ""); // $NON-NLS-1$
 
         p = property(RANDOM_SEED);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, ""); // $NON-NLS-1$
 
         createPropertyGroup(OPTIONS_GROUP, new String[] { PER_THREAD, });
 
         p = property(PER_THREAD);
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
+        p.setValue(DEFAULT, false);
     }
 }
diff --git a/src/components/src/main/java/org/apache/jmeter/control/ForeachController.java b/src/components/src/main/java/org/apache/jmeter/control/ForeachController.java
index d80b94f038..27fccc4297 100644
--- a/src/components/src/main/java/org/apache/jmeter/control/ForeachController.java
+++ b/src/components/src/main/java/org/apache/jmeter/control/ForeachController.java
@@ -167,7 +167,7 @@ public class ForeachController extends GenericController implements Serializable
             variables.putObject(getReturnVal(), currentVariable);
             if (log.isDebugEnabled()) {
                 log.debug("{} : Found in vars:{}, isDone:{}",
-                        getName(), inputVariable, Boolean.FALSE);
+                        getName(), inputVariable, false);
 
             }
             return false;
diff --git a/src/components/src/main/java/org/apache/jmeter/control/gui/CriticalSectionControllerGui.java b/src/components/src/main/java/org/apache/jmeter/control/gui/CriticalSectionControllerGui.java
index 467d7a1adf..a3af9fec83 100644
--- a/src/components/src/main/java/org/apache/jmeter/control/gui/CriticalSectionControllerGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/control/gui/CriticalSectionControllerGui.java
@@ -90,8 +90,7 @@ public class CriticalSectionControllerGui extends AbstractControllerGui {
     @Override
     public void configure(TestElement element) {
         super.configure(element);
-        if (element instanceof CriticalSectionController) {
-            CriticalSectionController controller = (CriticalSectionController) element;
+        if (element instanceof CriticalSectionController controller) {
             tfLockName.setText(controller.getLockName());
         }
 
@@ -113,8 +112,7 @@ public class CriticalSectionControllerGui extends AbstractControllerGui {
     @Override
     public void modifyTestElement(TestElement controller) {
         configureTestElement(controller);
-        if (controller instanceof CriticalSectionController) {
-            CriticalSectionController csController = (CriticalSectionController) controller;
+        if (controller instanceof CriticalSectionController csController) {
             csController.setLockName(tfLockName.getText());
         }
     }
diff --git a/src/components/src/main/java/org/apache/jmeter/control/gui/ForeachControlPanel.java b/src/components/src/main/java/org/apache/jmeter/control/gui/ForeachControlPanel.java
index 67cd2fad94..009e1a8f49 100644
--- a/src/components/src/main/java/org/apache/jmeter/control/gui/ForeachControlPanel.java
+++ b/src/components/src/main/java/org/apache/jmeter/control/gui/ForeachControlPanel.java
@@ -132,8 +132,7 @@ public class ForeachControlPanel extends AbstractControllerGui {
     @Override
     public void modifyTestElement(TestElement lc) {
         configureTestElement(lc);
-        if (lc instanceof ForeachController) {
-            ForeachController fec = (ForeachController) lc;
+        if (lc instanceof ForeachController fec) {
             fec.setInputVal(inputVal.getText());
             fec.setStartIndex(startIndex.getText());
             fec.setEndIndex(endIndex.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/control/gui/ModuleControllerGui.java b/src/components/src/main/java/org/apache/jmeter/control/gui/ModuleControllerGui.java
index 0cf853e2ff..54db597d84 100644
--- a/src/components/src/main/java/org/apache/jmeter/control/gui/ModuleControllerGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/control/gui/ModuleControllerGui.java
@@ -120,7 +120,7 @@ public class ModuleControllerGui extends AbstractControllerGui implements Action
 
             private static final long serialVersionUID = 4062816201792954617L;
 
-            private boolean isSelectedPathAllowed(DefaultMutableTreeNode lastSelected) {
+            private static boolean isSelectedPathAllowed(DefaultMutableTreeNode lastSelected) {
                 JMeterTreeNode tn = null;
                 if (lastSelected != null && lastSelected.getUserObject() instanceof JMeterTreeNode) {
                     tn = (JMeterTreeNode) lastSelected.getUserObject();
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/BoundaryExtractor.java b/src/components/src/main/java/org/apache/jmeter/extractor/BoundaryExtractor.java
index 6ae48f346d..ea3a017dd8 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/BoundaryExtractor.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/BoundaryExtractor.java
@@ -403,7 +403,7 @@ public class BoundaryExtractor extends AbstractScopedTestElement implements Post
 
     public boolean useBody() {
         String prop = getPropertyAsString(MATCH_AGAINST);
-        return prop.length() == 0 || USE_BODY.equalsIgnoreCase(prop);
+        return prop.isEmpty() || USE_BODY.equalsIgnoreCase(prop);
     }
 
     public boolean useUnescapedBody() {
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/DebugPostProcessorBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/extractor/DebugPostProcessorBeanInfo.java
index 14cf586ac2..85f2c3b1e9 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/DebugPostProcessorBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/DebugPostProcessorBeanInfo.java
@@ -29,28 +29,28 @@ public class DebugPostProcessorBeanInfo extends BeanInfoSupport {
         PropertyDescriptor p;
 
         p = property("displaySamplerProperties");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
+        p.setValue(DEFAULT, true);
 
         p = property("displayJMeterVariables");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
+        p.setValue(DEFAULT, true);
 
         p = property("displayJMeterProperties");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
+        p.setValue(DEFAULT, false);
 
         p = property("displaySystemProperties");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
+        p.setValue(DEFAULT, false);
     }
 
 }
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/HtmlExtractor.java b/src/components/src/main/java/org/apache/jmeter/extractor/HtmlExtractor.java
index 360f0666df..6af386a896 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/HtmlExtractor.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/HtmlExtractor.java
@@ -87,7 +87,7 @@ public class HtmlExtractor extends AbstractScopedTestElement implements PostProc
         int matchNumber = getMatchNumber();
         final String defaultValue = getDefaultValue();
 
-        if (defaultValue.length() > 0  || isEmptyDefaultValue()) {
+        if (!defaultValue.isEmpty() || isEmptyDefaultValue()) {
             // Only replace default if it is provided or empty default value is explicitly requested
             vars.put(refName, defaultValue);
         }
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/RegexExtractor.java b/src/components/src/main/java/org/apache/jmeter/extractor/RegexExtractor.java
index 6c6f7077f2..1199df9bb6 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/RegexExtractor.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/RegexExtractor.java
@@ -436,8 +436,8 @@ public class RegexExtractor extends AbstractScopedTestElement implements PostPro
             if(log.isDebugEnabled()) {
                 log.debug("RegexExtractor: Template piece {} ({})", obj, obj.getClass());
             }
-            if (obj instanceof Integer) {
-                result.append(match.group((Integer) obj));
+            if (obj instanceof Integer i) {
+                result.append(match.group(i));
             } else {
                 result.append(obj);
             }
@@ -452,8 +452,8 @@ public class RegexExtractor extends AbstractScopedTestElement implements PostPro
             if(log.isDebugEnabled()) {
                 log.debug("RegexExtractor: Template piece {} ({})", obj, obj.getClass());
             }
-            if (obj instanceof Integer) {
-                result.append(match.group((Integer) obj));
+            if (obj instanceof Integer i) {
+                result.append(match.group(i));
             } else {
                 result.append(obj);
             }
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/XPath2Extractor.java b/src/components/src/main/java/org/apache/jmeter/extractor/XPath2Extractor.java
index 1d51ad4e15..aaa672b0ab 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/XPath2Extractor.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/XPath2Extractor.java
@@ -115,7 +115,7 @@ public class XPath2Extractor
             if (isScopeVariable()){
                 String inputString=vars.get(getVariableName());
                 if(inputString != null) {
-                    if(inputString.length()>0) {
+                    if(!inputString.isEmpty()) {
                         getValuesForXPath(getXPathQuery(), matches, matchNumber, inputString);
                     }
                 } else {
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/XPathExtractor.java b/src/components/src/main/java/org/apache/jmeter/extractor/XPathExtractor.java
index 170435f926..dc910e70f6 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/XPathExtractor.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/XPathExtractor.java
@@ -129,7 +129,7 @@ public class XPathExtractor extends AbstractScopedTestElement implements
             if (isScopeVariable()){
                 String inputString=vars.get(getVariableName());
                 if(inputString != null) {
-                    if(inputString.length()>0) {
+                    if(!inputString.isEmpty()) {
                         Document d =  parseResponse(inputString);
                         getValuesForXPath(d,getXPathQuery(), matches, matchNumber);
                     }
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/gui/BoundaryExtractorGui.java b/src/components/src/main/java/org/apache/jmeter/extractor/gui/BoundaryExtractorGui.java
index b3f1f041da..6245ec523a 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/gui/BoundaryExtractorGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/gui/BoundaryExtractorGui.java
@@ -92,8 +92,7 @@ public class BoundaryExtractorGui extends AbstractPostProcessorGui {
     @Override
     public void configure(TestElement el) {
         super.configure(el);
-        if (el instanceof BoundaryExtractor){
-            BoundaryExtractor boundary = (BoundaryExtractor) el;
+        if (el instanceof BoundaryExtractor boundary){
             showScopeSettings(boundary, true);
             useHeaders.setSelected(boundary.useHeaders());
             useRequestHeaders.setSelected(boundary.useRequestHeaders());
@@ -130,8 +129,7 @@ public class BoundaryExtractorGui extends AbstractPostProcessorGui {
     @Override
     public void modifyTestElement(TestElement extractor) {
         super.configureTestElement(extractor);
-        if (extractor instanceof BoundaryExtractor) {
-            BoundaryExtractor boundary = (BoundaryExtractor) extractor;
+        if (extractor instanceof BoundaryExtractor boundary) {
             saveScopeSettings(boundary);
             boundary.setUseField(group.getSelection().getActionCommand());
             boundary.setRefName(refNameField.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/gui/HtmlExtractorGui.java b/src/components/src/main/java/org/apache/jmeter/extractor/gui/HtmlExtractorGui.java
index 2dc6d69895..0f6c62528b 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/gui/HtmlExtractorGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/gui/HtmlExtractorGui.java
@@ -77,8 +77,7 @@ public class HtmlExtractorGui extends AbstractPostProcessorGui {
     @Override
     public void configure(TestElement el) {
         super.configure(el);
-        if (el instanceof HtmlExtractor){
-            HtmlExtractor htmlExtractor = (HtmlExtractor) el;
+        if (el instanceof HtmlExtractor htmlExtractor){
             showScopeSettings(htmlExtractor, true);
             expressionField.setText(htmlExtractor.getExpression());
             attributeField.setText(htmlExtractor.getAttribute());
@@ -108,8 +107,7 @@ public class HtmlExtractorGui extends AbstractPostProcessorGui {
     @Override
     public void modifyTestElement(TestElement extractor) {
         super.configureTestElement(extractor);
-        if (extractor instanceof HtmlExtractor) {
-            HtmlExtractor htmlExtractor = (HtmlExtractor) extractor;
+        if (extractor instanceof HtmlExtractor htmlExtractor) {
             saveScopeSettings(htmlExtractor);
             htmlExtractor.setRefName(refNameField.getText());
             htmlExtractor.setExpression(expressionField.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/gui/RegexExtractorGui.java b/src/components/src/main/java/org/apache/jmeter/extractor/gui/RegexExtractorGui.java
index 02aeef2c00..de0ea98115 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/gui/RegexExtractorGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/gui/RegexExtractorGui.java
@@ -76,8 +76,7 @@ public class RegexExtractorGui extends AbstractPostProcessorGui {
     @Override
     public void configure(TestElement el) {
         super.configure(el);
-        if (el instanceof RegexExtractor){
-            RegexExtractor re = (RegexExtractor) el;
+        if (el instanceof RegexExtractor re){
             showScopeSettings(re, true);
             useHeaders.setSelected(re.useHeaders());
             useRequestHeaders.setSelected(re.useRequestHeaders());
@@ -114,8 +113,7 @@ public class RegexExtractorGui extends AbstractPostProcessorGui {
     @Override
     public void modifyTestElement(TestElement extractor) {
         super.configureTestElement(extractor);
-        if (extractor instanceof RegexExtractor) {
-            RegexExtractor regex = (RegexExtractor) extractor;
+        if (extractor instanceof RegexExtractor regex) {
             saveScopeSettings(regex);
             regex.setUseField(group.getSelection().getActionCommand());
             regex.setRefName(refNameField.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/gui/XPath2ExtractorGui.java b/src/components/src/main/java/org/apache/jmeter/extractor/gui/XPath2ExtractorGui.java
index e6b2523ac4..7a178f6377 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/gui/XPath2ExtractorGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/gui/XPath2ExtractorGui.java
@@ -89,8 +89,7 @@ public class XPath2ExtractorGui extends AbstractPostProcessorGui{ // NOSONAR Ign
     @Override
     public void modifyTestElement(TestElement extractor) {
         super.configureTestElement(extractor);
-        if (extractor instanceof XPath2Extractor) {
-            XPath2Extractor xpath = (XPath2Extractor) extractor;
+        if (extractor instanceof XPath2Extractor xpath) {
             saveScopeSettings(xpath);
             xpath.setDefaultValue(defaultField.getText());
             xpath.setRefName(refNameField.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/gui/XPathExtractorGui.java b/src/components/src/main/java/org/apache/jmeter/extractor/gui/XPathExtractorGui.java
index 0370531652..a7454b7f5e 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/gui/XPathExtractorGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/gui/XPathExtractorGui.java
@@ -95,8 +95,7 @@ public class XPathExtractorGui extends AbstractPostProcessorGui {
     @Override
     public void modifyTestElement(TestElement extractor) {
         super.configureTestElement(extractor);
-        if ( extractor instanceof XPathExtractor){
-            XPathExtractor xpath = (XPathExtractor)extractor;
+        if (extractor instanceof XPathExtractor xpath){
             saveScopeSettings(xpath);
             xpath.setDefaultValue(defaultField.getText());
             xpath.setRefName(refNameField.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/json/jmespath/JMESPathCache.java b/src/components/src/main/java/org/apache/jmeter/extractor/json/jmespath/JMESPathCache.java
index 2693c5a635..d5cd4f0599 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/json/jmespath/JMESPathCache.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/json/jmespath/JMESPathCache.java
@@ -34,7 +34,7 @@ public class JMESPathCache {
     private static final class JMESPathCacheLoader implements CacheLoader<String, Expression<JsonNode>> {
         final JmesPath<JsonNode> runtime;
 
-        public JMESPathCacheLoader() {
+        private JMESPathCacheLoader() {
             runtime = new JacksonRuntime(
                     new RuntimeConfiguration.Builder().withFunctionRegistry(FunctionRegistry.defaultRegistry()).build());
         }
@@ -57,7 +57,7 @@ public class JMESPathCache {
      * Initialization On Demand Holder pattern
      */
     private static class JMESPathCacheHolder {
-        public static final JMESPathCache INSTANCE = new JMESPathCache();
+        private static final JMESPathCache INSTANCE = new JMESPathCache();
     }
 
     /**
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/json/jmespath/gui/JMESPathExtractorGui.java b/src/components/src/main/java/org/apache/jmeter/extractor/json/jmespath/gui/JMESPathExtractorGui.java
index 149bc656d4..0961a178f7 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/json/jmespath/gui/JMESPathExtractorGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/json/jmespath/gui/JMESPathExtractorGui.java
@@ -88,8 +88,7 @@ public class JMESPathExtractorGui extends AbstractPostProcessorGui {
     @Override
     public void modifyTestElement(TestElement c) {
         super.configureTestElement(c);
-        if (c instanceof JMESPathExtractor) {
-            JMESPathExtractor config = (JMESPathExtractor) c;
+        if (c instanceof JMESPathExtractor config) {
             saveScopeSettings(config);
             config.setRefName(refNameField.getText());
             config.setJmesPathExpression(jmesPathExpressionField.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONManager.java b/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONManager.java
index 6d510318c4..830561d7b4 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONManager.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/JSONManager.java
@@ -92,8 +92,8 @@ public class JSONManager {
         if (obj instanceof Map) {
             return new JSONObject((Map<String, ?>) obj).toJSONString();
         }
-        if (obj instanceof JSONArray) {
-            return ((JSONArray)obj).toJSONString();
+        if (obj instanceof JSONArray objects) {
+            return objects.toJSONString();
         }
         return obj == null ? null : obj.toString();
     }
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/gui/JSONPostProcessorGui.java b/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/gui/JSONPostProcessorGui.java
index 2f005570cb..0394249b9a 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/gui/JSONPostProcessorGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/json/jsonpath/gui/JSONPostProcessorGui.java
@@ -93,8 +93,7 @@ public class JSONPostProcessorGui extends AbstractPostProcessorGui {
     @Override
     public void modifyTestElement(TestElement c) {
         super.configureTestElement(c);
-        if (c instanceof JSONPostProcessor) {
-            JSONPostProcessor config = (JSONPostProcessor) c;
+        if (c instanceof JSONPostProcessor config) {
             saveScopeSettings(config);
             config.setRefNames(refNamesField.getText());
             config.setJsonPathExpressions(jsonPathExpressionsField.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/extractor/json/render/AbstractRenderAsJsonRenderer.java b/src/components/src/main/java/org/apache/jmeter/extractor/json/render/AbstractRenderAsJsonRenderer.java
index 549679ff57..861009e7f9 100644
--- a/src/components/src/main/java/org/apache/jmeter/extractor/json/render/AbstractRenderAsJsonRenderer.java
+++ b/src/components/src/main/java/org/apache/jmeter/extractor/json/render/AbstractRenderAsJsonRenderer.java
@@ -105,7 +105,7 @@ abstract class AbstractRenderAsJsonRenderer implements ResultRenderer, ActionLis
      */
     protected void executeTester(String textToParse) {
         if (StringUtilities.isNotEmpty(textToParse)
-                && this.expressionField.getText().length() > 0) {
+                && !this.expressionField.getText().isEmpty()) {
             this.resultField.setText(process(textToParse));
             this.resultField.setCaretPosition(0); // go to first line
         }
@@ -202,8 +202,8 @@ abstract class AbstractRenderAsJsonRenderer implements ResultRenderer, ActionLis
     /** {@inheritDoc} */
     @Override
     public synchronized void setSamplerResult(Object userObject) {
-        if (userObject instanceof SampleResult) {
-            sampleResult = (SampleResult) userObject;
+        if (userObject instanceof SampleResult result) {
+            sampleResult = result;
         }
     }
 
diff --git a/src/components/src/main/java/org/apache/jmeter/gui/action/ExportTransactionAndSamplerNames.java b/src/components/src/main/java/org/apache/jmeter/gui/action/ExportTransactionAndSamplerNames.java
index cc988f7d9f..007d37ef73 100644
--- a/src/components/src/main/java/org/apache/jmeter/gui/action/ExportTransactionAndSamplerNames.java
+++ b/src/components/src/main/java/org/apache/jmeter/gui/action/ExportTransactionAndSamplerNames.java
@@ -87,7 +87,7 @@ public class ExportTransactionAndSamplerNames extends AbstractAction implements
      */
     private static class SamplerAndTransactionNameVisitor implements HashTreeTraverser {
         private final Set<String> listOfTransactions = new TreeSet<>();
-        public SamplerAndTransactionNameVisitor() {
+        private SamplerAndTransactionNameVisitor() {
             super();
         }
         @Override
@@ -113,10 +113,11 @@ public class ExportTransactionAndSamplerNames extends AbstractAction implements
         public void processPath() {
             // NOOP
         }
+
         /**
          * @return the listOfTransactions
          */
-        public Set<String> getListOfTransactions() {
+        private Set<String> getListOfTransactions() {
             return listOfTransactions;
         }
     }
diff --git a/src/components/src/main/java/org/apache/jmeter/modifiers/SampleTimeout.java b/src/components/src/main/java/org/apache/jmeter/modifiers/SampleTimeout.java
index 04a715a360..581d4cb13a 100644
--- a/src/components/src/main/java/org/apache/jmeter/modifiers/SampleTimeout.java
+++ b/src/components/src/main/java/org/apache/jmeter/modifiers/SampleTimeout.java
@@ -116,10 +116,9 @@ public class SampleTimeout extends AbstractTestElement implements Serializable,
         if (timeout <= 0) {
             return;
         }
-        if (!(samp instanceof Interruptible)) { // may be applied to a whole test
+        if (!(samp instanceof Interruptible sampler)) { // may be applied to a whole test
             return; // Cannot time out in this case
         }
-        final Interruptible sampler = (Interruptible) samp;
 
         Callable<Object> call = () -> {
             long start = System.nanoTime();
diff --git a/src/components/src/main/java/org/apache/jmeter/modifiers/UserParameters.java b/src/components/src/main/java/org/apache/jmeter/modifiers/UserParameters.java
index 2bbfcdbc98..4ae95284c9 100644
--- a/src/components/src/main/java/org/apache/jmeter/modifiers/UserParameters.java
+++ b/src/components/src/main/java/org/apache/jmeter/modifiers/UserParameters.java
@@ -118,7 +118,7 @@ public class UserParameters extends AbstractTestElement implements Serializable,
 
     private CollectionProperty getValues() {
         CollectionProperty threadValues = (CollectionProperty) getProperty(THREAD_VALUES);
-        if (threadValues.size() > 0) {
+        if (!threadValues.isEmpty()) {
             return (CollectionProperty) threadValues.get(getThreadContext().getThreadNum() % threadValues.size());
         }
         return new CollectionProperty("noname", new ArrayList<>());
diff --git a/src/components/src/main/java/org/apache/jmeter/modifiers/gui/CounterConfigGui.java b/src/components/src/main/java/org/apache/jmeter/modifiers/gui/CounterConfigGui.java
index 4eb17e2a7f..648d336702 100644
--- a/src/components/src/main/java/org/apache/jmeter/modifiers/gui/CounterConfigGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/modifiers/gui/CounterConfigGui.java
@@ -72,8 +72,7 @@ public class CounterConfigGui extends AbstractConfigGui implements ActionListene
      */
     @Override
     public void modifyTestElement(TestElement c) {
-        if (c instanceof CounterConfig) {
-            CounterConfig config = (CounterConfig) c;
+        if (c instanceof CounterConfig config) {
             config.setStart(startField.getText());
             config.setEnd(endField.getText());
             config.setIncrement(incrField.getText());
diff --git a/src/components/src/main/java/org/apache/jmeter/reporters/MailerModel.java b/src/components/src/main/java/org/apache/jmeter/reporters/MailerModel.java
index 6666bac9fe..1d905d64ff 100644
--- a/src/components/src/main/java/org/apache/jmeter/reporters/MailerModel.java
+++ b/src/components/src/main/java/org/apache/jmeter/reporters/MailerModel.java
@@ -345,19 +345,15 @@ public class MailerModel extends AbstractTestElement implements Serializable {
         if(mailAuthType != MailAuthType.NONE) {
             props.put(MAIL_SMTP_AUTH, "true");
             switch (mailAuthType) {
-                case SSL:
+                case SSL -> {
                     props.put(MAIL_SMTP_SOCKETFACTORY_CLASS,
                             "javax.net.ssl.SSLSocketFactory");
                     props.put(MAIL_SMTP_CHECK_SERVER_IDENTITY, true);
-                    break;
-                case TLS:
-                    props.put(MAIL_SMTP_STARTTLS,
-                            "true");
-                    break;
-
-                default:
-                    break;
                 }
+                case TLS -> props.put(MAIL_SMTP_STARTTLS, "true");
+                default -> {
+                }
+            }
         }
 
         if (StringUtilities.isNotEmpty(user)) {
diff --git a/src/components/src/main/java/org/apache/jmeter/sampler/DebugSamplerBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/sampler/DebugSamplerBeanInfo.java
index fe62566b21..a39355b033 100644
--- a/src/components/src/main/java/org/apache/jmeter/sampler/DebugSamplerBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/sampler/DebugSamplerBeanInfo.java
@@ -27,21 +27,21 @@ public class DebugSamplerBeanInfo extends BeanInfoSupport {
         PropertyDescriptor p;
 
         p = property("displayJMeterVariables");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
+        p.setValue(DEFAULT, true);
 
         p = property("displayJMeterProperties");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
+        p.setValue(DEFAULT, false);
 
         p = property("displaySystemProperties");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
+        p.setValue(DEFAULT, false);
     }
 }
diff --git a/src/components/src/main/java/org/apache/jmeter/timers/ConstantThroughputTimer.java b/src/components/src/main/java/org/apache/jmeter/timers/ConstantThroughputTimer.java
index 448e0cc268..9dc8d0baee 100644
--- a/src/components/src/main/java/org/apache/jmeter/timers/ConstantThroughputTimer.java
+++ b/src/components/src/main/java/org/apache/jmeter/timers/ConstantThroughputTimer.java
@@ -134,10 +134,12 @@ public class ConstantThroughputTimer extends AbstractTestElement implements Time
         return getPropertyAsDouble(THROUGHPUT);
     }
 
+    @SuppressWarnings("EnumOrdinal")
     public int getCalcMode() {
         return getPropertyAsInt(CALC_MODE, DEFAULT_CALC_MODE.ordinal());
     }
 
+    @SuppressWarnings("EnumOrdinal")
     public void setCalcMode(int mode) {
         Mode resolved = Mode.CACHED_VALUES[mode];
         setProperty(new IntegerProperty(CALC_MODE, resolved.ordinal()));
@@ -152,10 +154,8 @@ public class ConstantThroughputTimer extends AbstractTestElement implements Time
     public long delay() {
         long currentTime = System.currentTimeMillis();
 
-        /*
-         * If previous time is zero, then target will be in the past.
-         * This is what we want, so first sample is run without a delay.
-        */
+        // If previous time is zero, then target will be in the past.
+        // This is what we want, so first sample is run without a delay.
         long currentTarget = previousTime  + calculateDelay();
         if (currentTime > currentTarget) {
             // We're behind schedule -- try to catch up:
@@ -269,6 +269,7 @@ public class ConstantThroughputTimer extends AbstractTestElement implements Time
      * so the conversion only needs to happen once.
      */
     @Override
+    @SuppressWarnings("EnumOrdinal")
     public void setProperty(JMeterProperty property) {
         if (property instanceof StringProperty) {
             final String pn = property.getName();
@@ -303,6 +304,7 @@ public class ConstantThroughputTimer extends AbstractTestElement implements Time
     }
 
     // For access from test code
+    @SuppressWarnings("EnumOrdinal")
     void setMode(Mode newMode) {
         setCalcMode(newMode.ordinal());
     }
diff --git a/src/components/src/main/java/org/apache/jmeter/timers/ConstantThroughputTimerBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/timers/ConstantThroughputTimerBeanInfo.java
index 63db360d1f..0288460bb3 100644
--- a/src/components/src/main/java/org/apache/jmeter/timers/ConstantThroughputTimerBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/timers/ConstantThroughputTimerBeanInfo.java
@@ -26,6 +26,7 @@ import org.apache.jmeter.testbeans.BeanInfoSupport;
  */
 public class ConstantThroughputTimerBeanInfo extends BeanInfoSupport {
 
+    @SuppressWarnings("EnumOrdinal")
     public ConstantThroughputTimerBeanInfo() {
         super(ConstantThroughputTimer.class);
 
@@ -34,12 +35,12 @@ public class ConstantThroughputTimerBeanInfo extends BeanInfoSupport {
                 ConstantThroughputTimer.CALC_MODE }); //$NON-NLS-1$
 
         PropertyDescriptor p = property(ConstantThroughputTimer.THROUGHPUT); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 0.0);
 
         p = property(ConstantThroughputTimer.CALC_MODE, ConstantThroughputTimer.Mode.class); //$NON-NLS-1$
         p.setValue(DEFAULT, ConstantThroughputTimer.Mode.ThisThreadOnly.ordinal());
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE); // must be defined
+        p.setValue(NOT_UNDEFINED, true); // must be defined
     }
 
 }
diff --git a/src/components/src/main/java/org/apache/jmeter/timers/SyncTimer.java b/src/components/src/main/java/org/apache/jmeter/timers/SyncTimer.java
index 624e9d64dd..3943897f8d 100644
--- a/src/components/src/main/java/org/apache/jmeter/timers/SyncTimer.java
+++ b/src/components/src/main/java/org/apache/jmeter/timers/SyncTimer.java
@@ -52,14 +52,14 @@ public class SyncTimer extends AbstractTestElement implements Timer, Serializabl
         /**
          *
          */
-        public BarrierWrapper() {
+        private BarrierWrapper() {
             this.barrier = null;
         }
 
         /**
          * @param parties Number of parties
          */
-        public BarrierWrapper(int parties) {
+        private BarrierWrapper(int parties) {
             this.barrier = new CyclicBarrier(parties);
         }
 
@@ -67,7 +67,7 @@ public class SyncTimer extends AbstractTestElement implements Timer, Serializabl
          * Synchronized is required to ensure CyclicBarrier is initialized only once per Thread Group
          * @param parties Number of parties
          */
-        public synchronized void setup(int parties) {
+        private synchronized void setup(int parties) {
             if(this.barrier== null) {
                 this.barrier = new CyclicBarrier(parties);
             }
@@ -87,7 +87,7 @@ public class SyncTimer extends AbstractTestElement implements Timer, Serializabl
          * @see java.util.concurrent.CyclicBarrier#await()
          */
         @SuppressWarnings("UnusedMethod")
-        public int await() throws InterruptedException, BrokenBarrierException{
+        private int await() throws InterruptedException, BrokenBarrierException{
             return barrier.await();
         }
 
@@ -109,14 +109,14 @@ public class SyncTimer extends AbstractTestElement implements Timer, Serializabl
          *             if the specified time elapses
          * @see java.util.concurrent.CyclicBarrier#await()
          */
-        public int await(long timeout, TimeUnit timeUnit) throws InterruptedException, BrokenBarrierException, TimeoutException {
+        private int await(long timeout, TimeUnit timeUnit) throws InterruptedException, BrokenBarrierException, TimeoutException {
             return barrier.await(timeout, timeUnit);
         }
 
         /**
          * @see java.util.concurrent.CyclicBarrier#reset()
          */
-        public void reset() {
+        private void reset() {
             barrier.reset();
         }
 
diff --git a/src/components/src/main/java/org/apache/jmeter/timers/SyncTimerBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/timers/SyncTimerBeanInfo.java
index a3ae14de62..cb600bfdf1 100644
--- a/src/components/src/main/java/org/apache/jmeter/timers/SyncTimerBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/timers/SyncTimerBeanInfo.java
@@ -29,11 +29,11 @@ public class SyncTimerBeanInfo extends BeanInfoSupport {
         createPropertyGroup("grouping", new String[] { "groupSize", "timeoutInMs" });
 
         PropertyDescriptor p = property("groupSize");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 0);
 
         p = property("timeoutInMs");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 0L);
 
     }
diff --git a/src/components/src/main/java/org/apache/jmeter/timers/poissonarrivals/ConstantPoissonProcessGenerator.java b/src/components/src/main/java/org/apache/jmeter/timers/poissonarrivals/ConstantPoissonProcessGenerator.java
index 7410038783..ac633a132a 100644
--- a/src/components/src/main/java/org/apache/jmeter/timers/poissonarrivals/ConstantPoissonProcessGenerator.java
+++ b/src/components/src/main/java/org/apache/jmeter/timers/poissonarrivals/ConstantPoissonProcessGenerator.java
@@ -100,8 +100,8 @@ public class ConstantPoissonProcessGenerator implements EventProducer {
             if (log.isInfoEnabled()) {
                 StringBuilder sb = new StringBuilder();
                 sb.append("Generated ").append(events.position()).append(" timings (");
-                if (this.durationProvider instanceof AbstractTestElement) {
-                    sb.append(((AbstractTestElement) this.durationProvider).getName());
+                if (this.durationProvider instanceof AbstractTestElement abstractTestElement) {
+                    sb.append(abstractTestElement.getName());
                 }
                 sb.append(" ").append(samples).append(" required, rate ").append(throughput)
                         .append(", duration ").append(duration)
diff --git a/src/components/src/main/java/org/apache/jmeter/timers/poissonarrivals/PreciseThroughputTimerBeanInfo.java b/src/components/src/main/java/org/apache/jmeter/timers/poissonarrivals/PreciseThroughputTimerBeanInfo.java
index 46b7ddf3e1..9d4c82df02 100644
--- a/src/components/src/main/java/org/apache/jmeter/timers/poissonarrivals/PreciseThroughputTimerBeanInfo.java
+++ b/src/components/src/main/java/org/apache/jmeter/timers/poissonarrivals/PreciseThroughputTimerBeanInfo.java
@@ -38,15 +38,15 @@ public class PreciseThroughputTimerBeanInfo extends BeanInfoSupport {
 
         PropertyDescriptor p;
         p = property("throughput"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 100d);
 
         p = property("throughputPeriod"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 3600);
 
         p = property("duration"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 3600L);
 
         createPropertyGroup(
@@ -58,21 +58,21 @@ public class PreciseThroughputTimerBeanInfo extends BeanInfoSupport {
         );
 
         p = property("batchSize"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 1);
 
         p = property("batchThreadDelay"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 0);
 
 
         p = property("exactLimit"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 10000);
         p.setHidden(true);
 
         p = property("allowedThroughputSurplus"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 1.0d);
         p.setHidden(true);
 
@@ -84,7 +84,7 @@ public class PreciseThroughputTimerBeanInfo extends BeanInfoSupport {
         );
 
         p = property("randomSeed"); //$NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, 0L);
     }
 }
diff --git a/src/components/src/main/java/org/apache/jmeter/validation/ComponentTreeClonerForValidation.java b/src/components/src/main/java/org/apache/jmeter/validation/ComponentTreeClonerForValidation.java
index ea7af9b1dd..367be81af7 100644
--- a/src/components/src/main/java/org/apache/jmeter/validation/ComponentTreeClonerForValidation.java
+++ b/src/components/src/main/java/org/apache/jmeter/validation/ComponentTreeClonerForValidation.java
@@ -46,8 +46,7 @@ public class ComponentTreeClonerForValidation extends TreeClonerForValidation {
     @Override
     protected Object addNodeToTree(Object node) {
         Object clonedNode = super.addNodeToTree(node);
-        if (VALIDATION_TPC_FORCE_100_PERCENT && clonedNode instanceof ThroughputController) {
-            ThroughputController tc = (ThroughputController) clonedNode;
+        if (VALIDATION_TPC_FORCE_100_PERCENT && clonedNode instanceof ThroughputController tc) {
             if(tc.getStyle() == ThroughputController.BYPERCENT) {
                 tc.setPercentThroughput(100);
             }
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/ComparisonVisualizer.java b/src/components/src/main/java/org/apache/jmeter/visualizers/ComparisonVisualizer.java
index dedddbd54b..53ce9fa323 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/ComparisonVisualizer.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/ComparisonVisualizer.java
@@ -141,8 +141,8 @@ public class ComparisonVisualizer extends AbstractVisualizer implements Clearabl
                 AssertionResult[] results = sr.getAssertionResults();
                 CompareAssertionResult result = null;
                 for (AssertionResult r : results) {
-                    if (r instanceof CompareAssertionResult) {
-                        result = (CompareAssertionResult) r;
+                    if (r instanceof CompareAssertionResult compareAssertionResult) {
+                        result = compareAssertionResult;
                         break;
                     }
                 }
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/MailerVisualizer.java b/src/components/src/main/java/org/apache/jmeter/visualizers/MailerVisualizer.java
index 474581ad69..8b141defd6 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/MailerVisualizer.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/MailerVisualizer.java
@@ -431,8 +431,7 @@ public class MailerVisualizer extends AbstractVisualizer implements ActionListen
      */
     @Override
     public void stateChanged(ChangeEvent e) {
-        if (e.getSource() instanceof MailerModel) {
-            MailerModel testModel = (MailerModel) e.getSource();
+        if (e.getSource() instanceof MailerModel testModel) {
             updateVisualizer(testModel);
         } else {
             super.stateChanged(e);
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsBoundaryExtractor.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsBoundaryExtractor.java
index 77f701984e..8acc6aca62 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsBoundaryExtractor.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsBoundaryExtractor.java
@@ -84,8 +84,8 @@ public class RenderAsBoundaryExtractor implements ResultRenderer, ActionListener
      */
     private void executeAndShowBoundaryExtractorTester(String textToParse) {
         if (StringUtilities.isNotEmpty(textToParse)
-                && this.boundaryExtractorFieldLeft.getText().length() > 0
-                && this.boundaryExtractorFieldRight.getText().length() > 0) {
+                && !this.boundaryExtractorFieldLeft.getText().isEmpty()
+                && !this.boundaryExtractorFieldRight.getText().isEmpty()) {
             this.boundaryExtractorResultField.setText(process(textToParse));
             this.boundaryExtractorResultField.setCaretPosition(0); // go to first line
         }
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsCssJQuery.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsCssJQuery.java
index 73958fc31f..e635dd3a47 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsCssJQuery.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsCssJQuery.java
@@ -112,7 +112,7 @@ public class RenderAsCssJQuery implements ResultRenderer, ActionListener {
      */
     private void executeAndShowCssJqueryTester(String textToParse) {
         if (StringUtilities.isNotEmpty(textToParse)
-                && this.cssJqueryField.getText().length() > 0) {
+                && !this.cssJqueryField.getText().isEmpty()) {
             this.cssJqueryResultField.setText(process(textToParse));
             this.cssJqueryResultField.setCaretPosition(0); // go to first line
         }
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsHTML.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsHTML.java
index cd26262a15..34d92cbfaa 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsHTML.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsHTML.java
@@ -79,10 +79,8 @@ public class RenderAsHTML extends SamplerResultTab implements ResultRenderer {
 
         String html = response.substring(htmlIndex);
 
-        /*
-         * To disable downloading and rendering of images and frames, enable the
-         * editor-kit. The Stream property can then be
-         */
+        // To disable downloading and rendering of images and frames, enable the
+        // editor-kit. The Stream property can then be
         // Must be done before setContentType
         results.setEditorKitForContentType(TEXT_HTML, embedded ? defaultHtmlEditor : customisedEditor);
 
@@ -93,14 +91,12 @@ public class RenderAsHTML extends SamplerResultTab implements ResultRenderer {
             // Must be done after setContentType [Why?]
             results.getDocument().putProperty(Document.StreamDescriptionProperty, res.getURL());
         }
-        /*
-         * Get round problems parsing <META http-equiv='content-type'
-         * content='text/html; charset=utf-8'> See
-         * <a href="http://bz.apache.org/bugzilla/show_bug.cgi?id=23315">Bug 23315</a>
-         *
-         * Is this due to a bug in Java?
-         */
-        results.getDocument().putProperty("IgnoreCharsetDirective", Boolean.TRUE); // $NON-NLS-1$
+        // Get round problems parsing <META http-equiv='content-type'
+        // content='text/html; charset=utf-8'> See
+        // <a href="http://bz.apache.org/bugzilla/show_bug.cgi?id=23315">Bug 23315</a>
+        //
+        // Is this due to a bug in Java?
+        results.getDocument().putProperty("IgnoreCharsetDirective", true); // $NON-NLS-1$
 
         try {
             results.setText(html); // Bug can generate RTE
@@ -130,7 +126,7 @@ public class RenderAsHTML extends SamplerResultTab implements ResultRenderer {
         }
 
         private static class LocalHTMLFactory extends javax.swing.text.html.HTMLEditorKit.HTMLFactory {
-            /*
+            /**
              * Provide dummy implementations to suppress download and display of
              * related resources: - FRAMEs - IMAGEs TODO create better dummy
              * displays TODO suppress LINK somehow
@@ -138,8 +134,7 @@ public class RenderAsHTML extends SamplerResultTab implements ResultRenderer {
             @Override
             public View create(Element elem) {
                 Object o = elem.getAttributes().getAttribute(StyleConstants.NameAttribute);
-                if (o instanceof HTML.Tag) {
-                    HTML.Tag kind = (HTML.Tag) o;
+                if (o instanceof HTML.Tag kind) {
                     if (kind == HTML.Tag.FRAME) {
                         return new ComponentView(elem);
                     } else if (kind == HTML.Tag.IMG) {
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsJSON.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsJSON.java
index a94e4ee43a..470ba982b1 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsJSON.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsJSON.java
@@ -69,11 +69,11 @@ public class RenderAsJSON extends SamplerResultTab implements ResultRenderer {
         try {
             Object o = new JSONParser(JSONParser.DEFAULT_PERMISSIVE_MODE)
                     .parse(json);
-            if (o instanceof JSONObject) {
-                return ((JSONObject) o)
+            if (o instanceof JSONObject jsonObject) {
+                return jsonObject
                         .toJSONString(new PrettyJSONStyle(tabSeparator));
-            } else if (o instanceof JSONArray) {
-                return ((JSONArray) o)
+            } else if (o instanceof JSONArray objects) {
+                return objects
                         .toJSONString(new PrettyJSONStyle(tabSeparator));
             }
         } catch (ParseException e) {
@@ -92,7 +92,7 @@ public class RenderAsJSON extends SamplerResultTab implements ResultRenderer {
         private int level = 0;
         private final String indentString;
 
-        public PrettyJSONStyle(String indentString) {
+        private PrettyJSONStyle(String indentString) {
             this.indentString = indentString;
         }
 
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXML.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXML.java
index 22ca4d8c8f..a278369070 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXML.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXML.java
@@ -163,26 +163,23 @@ public class RenderAsXML extends SamplerResultTab
         }
     }
 
-    /*
-     *
+    /**
      * A Dom tree panel for to display response as tree view author <a
      * href="mailto:d.maung@mdl.com">Dave Maung</a>
      * TODO implement to find any nodes in the tree using TreePath.
-     *
      */
     private static class DOMTreePanel extends JPanel implements MouseListener {
 
         private static final long serialVersionUID = 6871690021183779153L;
 
-        private JTree domJTree;
         private ExpandPopupMenu popupMenu;
 
-        public DOMTreePanel(org.w3c.dom.Document document) {
+        private DOMTreePanel(org.w3c.dom.Document document) {
             super(new GridLayout(1, 0));
             try {
                 Node firstElement = getFirstElement(document);
                 DefaultMutableTreeNode top = new XMLDefaultMutableTreeNode(firstElement);
-                domJTree = new JTree(top);
+                JTree domJTree = new JTree(top);
                 domJTree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
                 domJTree.setShowsRootHandles(true);
                 domJTree.addMouseListener(this);
@@ -252,7 +249,12 @@ public class RenderAsXML extends SamplerResultTab
                     if (i % maxChar == 0 && i != 0) {
                         strBuf.append(separator);
                     }
-                    strBuf.append(encode(chars[i]));
+                    String encoded = encode(chars[i]);
+                    if (encoded != null) {
+                        strBuf.append(encoded);
+                    } else {
+                        strBuf.append(chars[i]);
+                    }
 
                 }
                 strBuf.append("</b></body></html>"); // $NON-NLS-1$
@@ -261,26 +263,13 @@ public class RenderAsXML extends SamplerResultTab
             }
 
             private static String encode(char c) {
-                String toReturn = String.valueOf(c);
-                switch (c) {
-                    case '<': // $NON-NLS-1$
-                        toReturn = "&lt;"; // $NON-NLS-1$
-                        break;
-                    case '>': // $NON-NLS-1$
-                        toReturn = "&gt;"; // $NON-NLS-1$
-                        break;
-                    case '\'': // $NON-NLS-1$
-                        toReturn = "&apos;"; // $NON-NLS-1$
-                        break;
-                    case '\"': // $NON-NLS-1$
-                        toReturn = "&quot;"; // $NON-NLS-1$
-                        break;
-                    default:
-                        // ignored
-                        break;
-
-                }
-                return toReturn;
+                return switch (c) {
+                    case '<' -> "&lt;"; // $NON-NLS-1$
+                    case '>' -> "&gt;"; // $NON-NLS-1$
+                    case '\'' -> "&apos;"; // $NON-NLS-1$
+                    case '\"' -> "&quot;"; // $NON-NLS-1$
+                    default -> null;
+                };
             }
         }
 
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXPath.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXPath.java
index 715e504d2c..4fa0689a41 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXPath.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXPath.java
@@ -127,7 +127,7 @@ public class RenderAsXPath implements ResultRenderer, ActionListener {
      */
     private void executeAndShowXPathTester(String textToParse, XPathExtractor extractor) {
         if (StringUtilities.isNotEmpty(textToParse)
-                && this.xpathExpressionField.getText().length() > 0) {
+                && !this.xpathExpressionField.getText().isEmpty()) {
             this.xpathResultField.setText(process(textToParse, extractor));
             this.xpathResultField.setCaretPosition(0); // go to first line
         }
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXPath2.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXPath2.java
index 9d11aced47..432d70398e 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXPath2.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXPath2.java
@@ -122,7 +122,7 @@ public class RenderAsXPath2 implements ResultRenderer, ActionListener {
      */
     private void executeAndShowXPathTester(String textToParse, XPath2Extractor extractor) {
         if (StringUtilities.isNotEmpty(textToParse)
-                && this.xpathExpressionField.getText().length() > 0) {
+                && !this.xpathExpressionField.getText().isEmpty()) {
             this.xpathResultField.setText(process(textToParse, extractor));
             this.xpathResultField.setCaretPosition(0); // go to first line
         }
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderInBrowser.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderInBrowser.java
index 4f3d71cb7d..2656051b3c 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RenderInBrowser.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RenderInBrowser.java
@@ -151,9 +151,6 @@ public class RenderInBrowser extends SamplerResultTab implements ResultRenderer
         return JMeterUtils.getResString("view_results_render_browser"); // $NON-NLS-1$
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.SamplerResultTab#clearData()
-     */
     @Override
     public void clearData() {
         super.clearData();
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RequestViewRaw.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RequestViewRaw.java
index b0caf1d562..6cdb3cfaa0 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RequestViewRaw.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RequestViewRaw.java
@@ -48,9 +48,6 @@ public class RequestViewRaw implements RequestView {
 
     private JPanel paneRaw; /** request pane content */
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.request.RequestView#init()
-     */
     @Override
     public void init() {
         paneRaw = new JPanel(new BorderLayout(0, 5));
@@ -78,22 +75,15 @@ public class RequestViewRaw implements RequestView {
 
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.request.RequestView#clearData()
-     */
     @Override
     public void clearData() {
         sampleDataField.setInitialText(""); //$NON-NLS-1$
         headerData.setInitialText(""); //$NON-NLS-1$
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.request.RequestView#setSamplerResult(java.lang.Object)
-     */
     @Override
     public void setSamplerResult(Object objectResult) {
-        if (objectResult instanceof SampleResult) {
-            SampleResult sampleResult = (SampleResult) objectResult;
+        if (objectResult instanceof SampleResult sampleResult) {
             // Don't display Request headers label if rh is null or empty
             String rh = sampleResult.getRequestHeaders();
             if (StringUtilities.isNotEmpty(rh)) {
@@ -112,17 +102,11 @@ public class RequestViewRaw implements RequestView {
         }
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.request.RequestView#getPanel()
-     */
     @Override
     public JPanel getPanel() {
         return paneRaw;
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.request.RequestView#getLabel()
-     */
     @Override
     public String getLabel() {
         return JMeterUtils.getResString(KEY_LABEL);
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RespTimeGraphChart.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RespTimeGraphChart.java
index fec8117dbd..5ad6429bd0 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RespTimeGraphChart.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RespTimeGraphChart.java
@@ -285,7 +285,7 @@ public class RespTimeGraphChart extends JPanel {
         double max = maxYAxisScale > 0 ? maxYAxisScale : getTopValue(findMax(_data), RoundingMode.UP); // define max scale y axis
         try {
             // if the title graph is empty, we can assume some default
-            if (_title.length() == 0 ) {
+            if (_title.isEmpty()) {
                 _title = JMeterUtils.getResString("graph_resp_time_title"); //$NON-NLS-1$
             }
             this.setPreferredSize(new Dimension(_width,_height));
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/RespTimeGraphVisualizer.java b/src/components/src/main/java/org/apache/jmeter/visualizers/RespTimeGraphVisualizer.java
index e0d4cf91d0..bb0b23b3d7 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/RespTimeGraphVisualizer.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/RespTimeGraphVisualizer.java
@@ -348,16 +348,16 @@ public class RespTimeGraphVisualizer extends AbstractVisualizer implements Actio
         if (!dynamicGraphSize.isSelected()) {
             String wstr = graphWidth.getText();
             String hstr = graphHeight.getText();
-            if (wstr.length() != 0) {
+            if (!wstr.isEmpty()) {
                 width = Integer.parseInt(wstr);
             }
-            if (hstr.length() != 0) {
+            if (!hstr.isEmpty()) {
                 height = Integer.parseInt(hstr);
             }
         }
 
         String yAxisStr = maxValueYAxisLabel.getText();
-        int maxYAxisScale = yAxisStr.length() == 0 ? 0 : Integer.parseInt(yAxisStr);
+        int maxYAxisScale = yAxisStr.isEmpty() ? 0 : Integer.parseInt(yAxisStr);
 
         graphPanel.setData(this.getData());
         graphPanel.setTitle(graphTitle.getText());
@@ -538,7 +538,7 @@ public class RespTimeGraphVisualizer extends AbstractVisualizer implements Actio
                 intervalValue = Integer.parseInt(intervalField.getText());
             }
             if (eventSource == applyFilterBtn && samplerSelection.isSelected() && samplerMatchLabel.getText() != null
-                    && samplerMatchLabel.getText().length() > 0) {
+                    && !samplerMatchLabel.getText().isEmpty()) {
                 pattern = createPattern(samplerMatchLabel.getText());
             } else if (forceReloadData) {
                 pattern = null;
@@ -742,7 +742,7 @@ public class RespTimeGraphVisualizer extends AbstractVisualizer implements Actio
     private int getIncrScaleYAxis() {
         int incrYAxisScale = 0;
         String iyas = incrScaleYAxis.getText();
-        if (iyas.length() != 0) {
+        if (!iyas.isEmpty()) {
             incrYAxisScale = Integer.parseInt(iyas);
         }
         return incrYAxisScale;
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/SamplerResultTab.java b/src/components/src/main/java/org/apache/jmeter/visualizers/SamplerResultTab.java
index 90819ac6c4..edb81c9cdf 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/SamplerResultTab.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/SamplerResultTab.java
@@ -251,8 +251,8 @@ public abstract class SamplerResultTab implements ResultRenderer {
         this.clearData();
         StyledDocument statsDoc = stats.getStyledDocument();
         try {
-            if (userObject instanceof SampleResult) {
-                sampleResult = (SampleResult) userObject;
+            if (userObject instanceof SampleResult sampleResult1) {
+                sampleResult = sampleResult1;
                 // We are displaying a SampleResult
                 setupTabPaneForSampleResult();
                 requestPanel.setSamplerResult(sampleResult);
@@ -326,20 +326,12 @@ public abstract class SamplerResultTab implements ResultRenderer {
                     }
                 }
 
-                Style style = null;
-                switch (responseLevel) {
-                case 3:
-                    style = statsDoc.getStyle(STYLE_REDIRECT);
-                    break;
-                case 4:
-                    style = statsDoc.getStyle(STYLE_CLIENT_ERROR);
-                    break;
-                case 5:
-                    style = statsDoc.getStyle(STYLE_SERVER_ERROR);
-                    break;
-                default: // quieten Findbugs
-                    break; // default - do nothing
-                }
+                Style style = switch (responseLevel) {
+                    case 3 -> statsDoc.getStyle(STYLE_REDIRECT);
+                    case 4 -> statsDoc.getStyle(STYLE_CLIENT_ERROR);
+                    case 5 -> statsDoc.getStyle(STYLE_SERVER_ERROR);
+                    default -> null;
+                };
 
                 statsBuff.append(JMeterUtils.getResString("view_results_response_code")).append(responseCode).append(NL); //$NON-NLS-1$
                 statsDoc.insertString(statsDoc.getLength(), statsBuff.toString(), style);
@@ -434,8 +426,8 @@ public abstract class SamplerResultTab implements ResultRenderer {
                     searchTextExtension.resetTextToFind();
                 }
 
-            } else if (userObject instanceof AssertionResult) {
-                assertionResult = (AssertionResult) userObject;
+            } else if (userObject instanceof AssertionResult result) {
+                assertionResult = result;
 
                 // We are displaying an AssertionResult
                 setupTabPaneForAssertionResult();
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/SearchTextExtension.java b/src/components/src/main/java/org/apache/jmeter/visualizers/SearchTextExtension.java
index ffaab0e89b..702daa6b9f 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/SearchTextExtension.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/SearchTextExtension.java
@@ -271,7 +271,7 @@ public class SearchTextExtension implements ActionListener, DocumentListener {
         @Override
         public boolean executeAndShowTextFind(Pattern pattern) {
             boolean found = false;
-            if (results != null && results.getText().length() > 0
+            if (results != null && !results.getText().isEmpty()
                     && pattern != null) {
 
                 log.debug("lastPosition={}", lastPosition);
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/SearchTreePanel.java b/src/components/src/main/java/org/apache/jmeter/visualizers/SearchTreePanel.java
index 14e4c7dea0..70422194e0 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/SearchTreePanel.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/SearchTreePanel.java
@@ -184,8 +184,8 @@ public class SearchTreePanel extends JPanel implements ActionListener {
 
         try {
             Searchable searchable;
-            if(userObject instanceof Searchable) {
-                searchable = (Searchable) userObject;
+            if(userObject instanceof Searchable searchable1) {
+                searchable = searchable1;
             } else {
                 return false;
             }
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/StatGraphVisualizer.java b/src/components/src/main/java/org/apache/jmeter/visualizers/StatGraphVisualizer.java
index 32703f1517..44aa4a038a 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/StatGraphVisualizer.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/StatGraphVisualizer.java
@@ -590,20 +590,20 @@ public class StatGraphVisualizer extends AbstractVisualizer implements Clearable
         if (!dynamicGraphSize.isSelected()) {
             String wstr = graphWidth.getText();
             String hstr = graphHeight.getText();
-            if (wstr.length() != 0) {
+            if (!wstr.isEmpty()) {
                 width = Integer.parseInt(wstr);
             }
-            if (hstr.length() != 0) {
+            if (!hstr.isEmpty()) {
                 height = Integer.parseInt(hstr);
             }
         }
 
-        if (lstr.length() == 0) {
+        if (lstr.isEmpty()) {
             lstr = "20";//$NON-NLS-1$
         }
         int maxLength = Integer.parseInt(lstr);
         String yAxisStr = maxValueYAxisLabel.getText();
-        int maxYAxisScale = yAxisStr.length() == 0 ? 0 : Integer.parseInt(yAxisStr);
+        int maxYAxisScale = yAxisStr.isEmpty() ? 0 : Integer.parseInt(yAxisStr);
 
         graphPanel.setData(this.getData());
         graphPanel.setTitle(graphTitle.getText());
@@ -776,19 +776,18 @@ public class StatGraphVisualizer extends AbstractVisualizer implements Clearable
         // Not 'else if' because forceReloadData
         if (eventSource == applyFilterBtn || forceReloadData) {
             if (columnSelection.isSelected() && columnMatchLabel.getText() != null
-                    && columnMatchLabel.getText().length() > 0) {
+                    && !columnMatchLabel.getText().isEmpty()) {
                 pattern = createPattern(columnMatchLabel.getText());
             } else if (forceReloadData) {
                 pattern = null;
             }
-            if (getFile() != null && getFile().length() > 0) {
+            if (getFile() != null && !getFile().isEmpty()) {
                 clearData();
                 FilePanel filePanel = (FilePanel) getFilePanel();
                 filePanel.actionPerformed(event);
             }
-        } else if (eventSource instanceof JButton) {
+        } else if (eventSource instanceof JButton btn) {
             // Changing color for column
-            JButton btn = (JButton) eventSource;
             if (btn.getName() != null) {
                 try {
                     BarGraph bar = eltList.get(Integer.parseInt(btn.getName()));
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/StatVisualizer.java b/src/components/src/main/java/org/apache/jmeter/visualizers/StatVisualizer.java
index 50dac1af03..eafeb9fd64 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/StatVisualizer.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/StatVisualizer.java
@@ -122,9 +122,7 @@ public class StatVisualizer extends AbstractVisualizer implements Clearable, Act
                     return newRow;
                 });
         synchronized (row) {
-            /*
-             * Synch is needed because multiple threads can update the counts.
-             */
+            // Synch is needed because multiple threads can update the counts.
             row.addSample(res);
         }
         SamplingStatCalculator tot = tableRows.get(TOTAL_ROW_LABEL);
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/TreeNodeRenderer.java b/src/components/src/main/java/org/apache/jmeter/visualizers/TreeNodeRenderer.java
index c154e5d2c7..97569935c4 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/TreeNodeRenderer.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/TreeNodeRenderer.java
@@ -57,9 +57,9 @@ public class TreeNodeRenderer extends DefaultTreeCellRenderer {
             boolean leaf, int row, boolean focus) {
         super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, focus);
         Object obj = ((DefaultMutableTreeNode) value).getUserObject();
-        if(obj instanceof SampleResult)
+        if(obj instanceof SampleResult sampleResult)
         {
-            if (!((SampleResult) obj).isSuccessful()) {
+            if (!sampleResult.isSuccessful()) {
                 this.setForeground(UIManager.getColor(JMeterUIDefaults.LABEL_ERROR_FOREGROUND));
                 this.setIcon(imageFailure);
             } else {
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/ViewResultsFullVisualizer.java b/src/components/src/main/java/org/apache/jmeter/visualizers/ViewResultsFullVisualizer.java
index 4c5f70aa28..5f74df6b34 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/ViewResultsFullVisualizer.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/ViewResultsFullVisualizer.java
@@ -394,8 +394,7 @@ implements ActionListener, TreeSelectionListener, Clearable, ItemListener {
             resultsRender.setSamplerResult(userObject);
             resultsRender.setupTabPane(); // Processes Assertions
             // display a SampleResult
-            if (userObject instanceof SampleResult) {
-                SampleResult sampleResult = (SampleResult) userObject;
+            if (userObject instanceof SampleResult sampleResult) {
                 if (isTextDataType(sampleResult)){
                     resultsRender.renderResult(sampleResult);
                 } else {
@@ -457,7 +456,7 @@ implements ActionListener, TreeSelectionListener, Clearable, ItemListener {
 
         // if no results render in jmeter.properties, load Standard (default)
         String defaultRenderer = expandToClassname(".RenderAsText"); // $NON-NLS-1$
-        if (VIEWERS_ORDER.length() > 0) {
+        if (!VIEWERS_ORDER.isEmpty()) {
             defaultRenderer = expandToClassname(VIEWERS_ORDER.split(",", 2)[0]);
         }
         ResultRenderer defaultObject = null;
@@ -475,7 +474,7 @@ implements ActionListener, TreeSelectionListener, Clearable, ItemListener {
             renderer.setBackgroundColor(getBackground());
             map.put(renderer.getClass().getName(), renderer);
         }
-        if (VIEWERS_ORDER.length() > 0) {
+        if (!VIEWERS_ORDER.isEmpty()) {
             Arrays.stream(VIEWERS_ORDER.split(","))
                     .map(ViewResultsFullVisualizer::expandToClassname)
                     .forEach(key -> {
@@ -584,10 +583,9 @@ implements ActionListener, TreeSelectionListener, Clearable, ItemListener {
             super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, focus);
             boolean failure = true;
             Object userObject = ((DefaultMutableTreeNode) value).getUserObject();
-            if (userObject instanceof SampleResult) {
-                failure = !((SampleResult) userObject).isSuccessful();
-            } else if (userObject instanceof AssertionResult) {
-                AssertionResult assertion = (AssertionResult) userObject;
+            if (userObject instanceof SampleResult sampleResult) {
+                failure = !sampleResult.isSuccessful();
+            } else if (userObject instanceof AssertionResult assertion) {
                 failure = assertion.isError() || assertion.isFailure();
             }
 
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/XMLDefaultMutableTreeNode.java b/src/components/src/main/java/org/apache/jmeter/visualizers/XMLDefaultMutableTreeNode.java
index 8858d3bb1e..68509af072 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/XMLDefaultMutableTreeNode.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/XMLDefaultMutableTreeNode.java
@@ -89,25 +89,13 @@ public class XMLDefaultMutableTreeNode extends DefaultMutableTreeNode {
     private static void initNode(Node node, XMLDefaultMutableTreeNode mTreeNode) throws SAXException {
 
         switch (node.getNodeType()) {
-        case Node.ELEMENT_NODE:
-            initElementNode(node, mTreeNode);
-            break;
-
-        case Node.TEXT_NODE:
-            initTextNode((Text) node, mTreeNode);
-            break;
-
-        case Node.CDATA_SECTION_NODE:
-            initCDATASectionNode((CDATASection) node, mTreeNode);
-            break;
-        case Node.COMMENT_NODE:
-            initCommentNode((Comment) node, mTreeNode);
-            break;
-
-        default:
+            case Node.ELEMENT_NODE -> initElementNode(node, mTreeNode);
+            case Node.TEXT_NODE -> initTextNode((Text) node, mTreeNode);
+            case Node.CDATA_SECTION_NODE -> initCDATASectionNode((CDATASection) node, mTreeNode);
+            case Node.COMMENT_NODE -> initCommentNode((Comment) node, mTreeNode);
+            default -> {
+            }
             // if other node type, we will just skip it
-            break;
-
         }
 
     }
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/BackendListener.java b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/BackendListener.java
index 4842f923ba..fe6291c406 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/BackendListener.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/BackendListener.java
@@ -94,7 +94,7 @@ public class BackendListener
     // Create unique object as marker for end of queue
     private static final transient SampleResult FINAL_SAMPLE_RESULT = new SampleResult();
 
-    /*
+    /**
      * This is needed for distributed testing where there is 1 instance
      * per server. But we need the total to be shared.
      */
@@ -111,7 +111,7 @@ public class BackendListener
         setArguments(new Arguments());
     }
 
-    /*
+    /**
      * Ensure that the required class variables are cloned,
      * as this is not currently done by the super-implementation.
      */
@@ -205,7 +205,11 @@ public class BackendListener
                         }
                         // try to process as many as possible
                         // The == comparison is not a mistake
-                        while (!(endOfLoop = sampleResult == FINAL_SAMPLE_RESULT) && sampleResult != null) {
+                        while (sampleResult != null) {
+                            endOfLoop = sampleResult == FINAL_SAMPLE_RESULT;
+                            if (endOfLoop) {
+                                break;
+                            }
                             sampleResults.add(sampleResult);
                             if (isDebugEnabled) {
                                 log.debug("Thread: {} polling from queue: {}", Thread.currentThread().getName(),
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/BackendListenerGui.java b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/BackendListenerGui.java
index 0a7f3337ba..32e0c2c95a 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/BackendListenerGui.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/BackendListenerGui.java
@@ -296,9 +296,6 @@ public class BackendListenerGui extends AbstractListenerGui implements ActionLis
         backendListener.setQueueSize(queueSize.getText());
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.gui.AbstractJMeterGuiComponent#clearGui()
-     */
     @Override
     public void clearGui() {
         super.clearGui();
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/ErrorMetric.java b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/ErrorMetric.java
index 9ae7694998..a0ec17467d 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/ErrorMetric.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/ErrorMetric.java
@@ -79,11 +79,10 @@ public class ErrorMetric {
 
     @Override
     public boolean equals(Object other) {
-        if (!(other instanceof ErrorMetric)) {
+        if (!(other instanceof ErrorMetric otherError)) {
             return false;
         }
 
-        ErrorMetric otherError = (ErrorMetric) other;
         return getResponseCode().equalsIgnoreCase(otherError.getResponseCode())
                 && getResponseMessage().equalsIgnoreCase(otherError.getResponseMessage());
 
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/PickleGraphiteMetricsSender.java b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/PickleGraphiteMetricsSender.java
index 99267ae937..0069c885ed 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/PickleGraphiteMetricsSender.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/PickleGraphiteMetricsSender.java
@@ -92,13 +92,6 @@ class PickleGraphiteMetricsSender extends AbstractGraphiteMetricsSender {
         return metrics;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.visualizers.backend.graphite.GraphiteMetricsSender#
-     * addMetric(long, java.lang.String, java.lang.String, java.lang.String)
-     */
     @Override
     public void addMetric(long timestamp, String contextName, String metricName, String metricValue) {
         String name = prefix + contextName + "." + metricName;
@@ -107,9 +100,6 @@ class PickleGraphiteMetricsSender extends AbstractGraphiteMetricsSender {
         }
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.backend.graphite.GraphiteMetricsSender#writeAndSendMetrics()
-     */
     @Override
     public void writeAndSendMetrics() {
         final List<MetricTuple> currentMetrics;
@@ -157,9 +147,6 @@ class PickleGraphiteMetricsSender extends AbstractGraphiteMetricsSender {
         }
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.backend.graphite.GraphiteMetricsSender#destroy()
-     */
     @Override
     public void destroy() {
         socketOutputStreamPool.close();
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/TextGraphiteMetricsSender.java b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/TextGraphiteMetricsSender.java
index a653fe51d1..362303067c 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/TextGraphiteMetricsSender.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/TextGraphiteMetricsSender.java
@@ -76,9 +76,6 @@ class TextGraphiteMetricsSender extends AbstractGraphiteMetricsSender {
         return metrics;
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.backend.graphite.GraphiteMetricsSender#addMetric(long, java.lang.String, java.lang.String, java.lang.String)
-     */
     @Override
     public void addMetric(long timestamp, String contextName, String metricName, String metricValue) {
         String name = prefix + contextName + "." + metricName;
@@ -87,9 +84,6 @@ class TextGraphiteMetricsSender extends AbstractGraphiteMetricsSender {
         }
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.backend.graphite.GraphiteMetricsSender#writeAndSendMetrics()
-     */
     @Override
     public void writeAndSendMetrics() {
         final List<MetricTuple> currentMetrics;
@@ -137,9 +131,6 @@ class TextGraphiteMetricsSender extends AbstractGraphiteMetricsSender {
         }
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.visualizers.backend.graphite.GraphiteMetricsSender#destroy()
-     */
     @Override
     public void destroy() {
         socketOutputStreamPool.close();
diff --git a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/influxdb/HttpMetricsSender.java b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/influxdb/HttpMetricsSender.java
index 6e2c2e25d4..3cd55edd3e 100644
--- a/src/components/src/main/java/org/apache/jmeter/visualizers/backend/influxdb/HttpMetricsSender.java
+++ b/src/components/src/main/java/org/apache/jmeter/visualizers/backend/influxdb/HttpMetricsSender.java
@@ -197,12 +197,10 @@ class HttpMetricsSender extends AbstractInfluxdbMetricsSender {
                 @Override
                 public void completed(final HttpResponse response) {
                     int code = response.getStatusLine().getStatusCode();
-                    /*
-                     * If your write request received HTTP
-                     * 204 No Content: it was a success!
-                     * 4xx: InfluxDB could not understand the request.
-                     * 5xx: The system is overloaded or significantly impaired.
-                     */
+                    // If your write request received HTTP
+                    // 204 No Content: it was a success!
+                    // 4xx: InfluxDB could not understand the request.
+                    // 5xx: The system is overloaded or significantly impaired.
                     if (MetricUtils.isSuccessCode(code)) {
                         if (log.isDebugEnabled()) {
                             log.debug("Success, number of metrics written: {}", copyMetrics.size());
diff --git a/src/components/src/test/java/org/apache/jmeter/assertions/SizeAssertionTest.java b/src/components/src/test/java/org/apache/jmeter/assertions/SizeAssertionTest.java
index 28215b65d4..6fcc2db971 100644
--- a/src/components/src/test/java/org/apache/jmeter/assertions/SizeAssertionTest.java
+++ b/src/components/src/test/java/org/apache/jmeter/assertions/SizeAssertionTest.java
@@ -37,7 +37,11 @@ public class SizeAssertionTest extends JMeterTestCase {
     private SampleResult sample0;
     private SampleResult sample1;
     private AssertionResult result;
-    private final String data1 = "response Data\n" + "line 2\n\nEOF";
+    private final String data1 = """
+            response Data
+            line 2
+
+            EOF""";
     private final int data1Len = data1.length();
 
     @BeforeEach
diff --git a/src/components/src/test/java/org/apache/jmeter/assertions/TestJSONPathAssertion.java b/src/components/src/test/java/org/apache/jmeter/assertions/TestJSONPathAssertion.java
index 59e442aa68..f39fe6d08d 100644
--- a/src/components/src/test/java/org/apache/jmeter/assertions/TestJSONPathAssertion.java
+++ b/src/components/src/test/java/org/apache/jmeter/assertions/TestJSONPathAssertion.java
@@ -319,19 +319,20 @@ class TestJSONPathAssertion {
     @Test
     void testGetResult_match_msg_problem2() {
         SampleResult samplerResult = new SampleResult();
-        String str = "{\n" +
-                " \"code\":200,\n" +
-                " \"contact\":{\n" +
-                "   \"id\":28071,\n" +
-                "   \"description\":\"test description\",\n" +
-                "   \"info\":{\n" +
-                "       \"ngn_number\":[\n" +
-                "           \"2003\",\n" +
-                "           \"2004\"\n" +
-                "       ]\n" +
-                "   }\n" +
-                " }\n" +
-                "}";
+        String str = """
+                {
+                 "code":200,
+                 "contact":{
+                   "id":28071,
+                   "description":"test description",
+                   "info":{
+                       "ngn_number":[
+                           "2003",
+                           "2004"
+                       ]
+                   }
+                 }
+                }""";
         samplerResult.setResponseData(str.getBytes(Charset.defaultCharset()));
 
         JSONPathAssertion instance = new JSONPathAssertion();
diff --git a/src/components/src/test/java/org/apache/jmeter/assertions/XMLSchemaAssertionTest.java b/src/components/src/test/java/org/apache/jmeter/assertions/XMLSchemaAssertionTest.java
index 62e60b5630..a3e6500d4f 100644
--- a/src/components/src/test/java/org/apache/jmeter/assertions/XMLSchemaAssertionTest.java
+++ b/src/components/src/test/java/org/apache/jmeter/assertions/XMLSchemaAssertionTest.java
@@ -52,7 +52,7 @@ public class XMLSchemaAssertionTest extends JMeterTestCase {
         jmctx.setPreviousResult(result);
     }
 
-    private ByteArrayOutputStream readBA(String name) throws IOException {
+    private static ByteArrayOutputStream readBA(String name) throws IOException {
         ByteArrayOutputStream baos = new ByteArrayOutputStream(1000);
         try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream(findTestFile(name)))) {
             int len = 0;
@@ -64,7 +64,7 @@ public class XMLSchemaAssertionTest extends JMeterTestCase {
         return baos;
     }
 
-    private byte[] readFile(String name) throws IOException {
+    private static byte[] readFile(String name) throws IOException {
         try (ByteArrayOutputStream baos = readBA(name)) {
             return baos.toByteArray();
         }
diff --git a/src/components/src/test/java/org/apache/jmeter/assertions/XPathAssertionTest.java b/src/components/src/test/java/org/apache/jmeter/assertions/XPathAssertionTest.java
index 14538a1281..a33e4ba8f4 100644
--- a/src/components/src/test/java/org/apache/jmeter/assertions/XPathAssertionTest.java
+++ b/src/components/src/test/java/org/apache/jmeter/assertions/XPathAssertionTest.java
@@ -67,7 +67,7 @@ public class XPathAssertionTest extends JMeterTestCase {
         result.setResponseData(data, null);
     }
 
-    private ByteArrayOutputStream readBA(String name) throws IOException {
+    private static ByteArrayOutputStream readBA(String name) throws IOException {
         BufferedInputStream bis = new BufferedInputStream(new FileInputStream(findTestFile(name)));
         ByteArrayOutputStream baos = new ByteArrayOutputStream(1000);
         int len = 0;
@@ -79,7 +79,7 @@ public class XPathAssertionTest extends JMeterTestCase {
         return baos;
     }
 
-    private byte[] readFile(String name) throws IOException {
+    private static byte[] readFile(String name) throws IOException {
         return readBA(name).toByteArray();
     }
 
diff --git a/src/components/src/test/java/org/apache/jmeter/assertions/XmlAssertionTest.java b/src/components/src/test/java/org/apache/jmeter/assertions/XmlAssertionTest.java
index dfdd466465..bc35a1c505 100644
--- a/src/components/src/test/java/org/apache/jmeter/assertions/XmlAssertionTest.java
+++ b/src/components/src/test/java/org/apache/jmeter/assertions/XmlAssertionTest.java
@@ -40,8 +40,11 @@ public class XmlAssertionTest extends JMeterTestCase {
             + "Don't forget me this weekend!</body></note1>";
     private static final String VALID_XML = "<note><to>Tove</to><from>Jani</from><heading>Reminder</heading><body>Don't forget me this weekend!</body></note>";
     private static final String NO_XML = "response Data";
-    private static final String UNSECURE_XML = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\n" + "<!DOCTYPE foo [\n"
-            + "   <!ENTITY xxe SYSTEM \"file:///etc/passwd\" > ]>\n" + "<foo>&xxe;</foo>";
+    private static final String UNSECURE_XML = """
+            <?xml version="1.0" encoding="ISO-8859-1"?>
+            <!DOCTYPE foo [
+               <!ENTITY xxe SYSTEM "file:///etc/passwd" > ]>
+            <foo>&xxe;</foo>""";
 
     @BeforeEach
     public void setUp() {
diff --git a/src/components/src/test/java/org/apache/jmeter/assertions/jmespath/TestJMESPathAssertion.java b/src/components/src/test/java/org/apache/jmeter/assertions/jmespath/TestJMESPathAssertion.java
index a5025d0019..0a87cccbdb 100644
--- a/src/components/src/test/java/org/apache/jmeter/assertions/jmespath/TestJMESPathAssertion.java
+++ b/src/components/src/test/java/org/apache/jmeter/assertions/jmespath/TestJMESPathAssertion.java
@@ -125,11 +125,23 @@ class TestJMESPathAssertion {
                         ComparisonType.USE_NO_REXEG, ResultNullity.EXPECT_NOT_NULL, "", ResultType.FAILURE,
                         AssertionResult.RESPONSE_WAS_NULL),
                 Arguments.of(InvertType.USE_NO_INVERT,
-                        "{\n" + "  \"reservations\": [\n" + "    {\n" + "      \"instances\": [\n"
-                                + "        {\"state\": \"running\"},\n" + "        {\"state\": \"stopped\"}\n"
-                                + "      ]\n" + "    },\n" + "    {\n" + "      \"instances\": [\n"
-                                + "        {\"state\": \"terminated\"},\n" + "        {\"state\": \"running\"}\n"
-                                + "      ]\n" + "    }\n" + "  ]\n" + "}",
+                        """
+                                {
+                                  "reservations": [
+                                    {
+                                      "instances": [
+                                        {"state": "running"},
+                                        {"state": "stopped"}
+                                      ]
+                                    },
+                                    {
+                                      "instances": [
+                                        {"state": "terminated"},
+                                        {"state": "running"}
+                                      ]
+                                    }
+                                  ]
+                                }""",
                         "reservations[*].instances[*].state", ValidationType.USE_VALIDATION,
                         ComparisonType.USE_NO_REXEG, ResultNullity.EXPECT_NOT_NULL,
                         "[[\"running\",\"stopped\"],[\"terminated\",\"running\"]]", ResultType.SUCCESS, ""),
diff --git a/src/components/src/test/java/org/apache/jmeter/config/TestCVSDataSet.java b/src/components/src/test/java/org/apache/jmeter/config/TestCVSDataSet.java
index 2edad0ab84..174a02aa50 100644
--- a/src/components/src/test/java/org/apache/jmeter/config/TestCVSDataSet.java
+++ b/src/components/src/test/java/org/apache/jmeter/config/TestCVSDataSet.java
@@ -208,7 +208,7 @@ public class TestCVSDataSet extends JMeterTestCase implements JMeterSerialTest {
         }
     }
 
-    private CSVDataSet initCSV(){
+    private static CSVDataSet initCSV(){
         CSVDataSet csv = new CSVDataSet();
         csv.setFilename(findTestPath("testfiles/unit/TestCVSDataSet.csv"));
         csv.setVariableNames("a,b,c");
diff --git a/src/components/src/test/java/org/apache/jmeter/control/TestWhileController.java b/src/components/src/test/java/org/apache/jmeter/control/TestWhileController.java
index 2e1a877dca..e630109f63 100644
--- a/src/components/src/test/java/org/apache/jmeter/control/TestWhileController.java
+++ b/src/components/src/test/java/org/apache/jmeter/control/TestWhileController.java
@@ -50,7 +50,7 @@ public class TestWhileController extends JMeterTestCase {
         jmvars.put(JMeterThread.LAST_SAMPLE_OK, Boolean.toString(status));
     }
 
-    private void setRunning(TestElement el) {
+    private static void setRunning(TestElement el) {
         PropertyIterator pi = el.propertyIterator();
         while (pi.hasNext()) {
             pi.next().setRunningVersion(true);
@@ -58,7 +58,7 @@ public class TestWhileController extends JMeterTestCase {
     }
 
     // Get next sample and its name
-    private String nextName(GenericController c) {
+    private static String nextName(GenericController c) {
         Sampler s = c.next();
         if (s == null) {
             return null;
@@ -154,7 +154,7 @@ public class TestWhileController extends JMeterTestCase {
         assertNull(nextName(controller));
     }
 
-    /*
+    /**
      * Generic Controller
      * - before
      * - While Controller ${VAR}
diff --git a/src/components/src/test/java/org/apache/jmeter/extractor/TestRegexExtractor.java b/src/components/src/test/java/org/apache/jmeter/extractor/TestRegexExtractor.java
index 4e39a7889e..d04385f1a8 100644
--- a/src/components/src/test/java/org/apache/jmeter/extractor/TestRegexExtractor.java
+++ b/src/components/src/test/java/org/apache/jmeter/extractor/TestRegexExtractor.java
@@ -48,13 +48,14 @@ public class TestRegexExtractor {
         extractor.setThreadContext(jmctx);
         extractor.setRefName("regVal");
         result = new SampleResult();
-        String data = "<company-xmlext-query-ret><row><value field=\"RetCode\">LIS_OK</value>\n" +
-                "<value field=\"RetCodeExtension\"></value><value field=\"alias\"></value>\n" +
-                "<value field=\"positioncount\"></value><value field=\"invalidpincount\">0</value>\n" +
-                "<value field=\"pinposition1\">1</value><value field=\"pinpositionvalue1\"></value>\n" +
-                "<value field=\"pinposition2\">5</value><value field=\"pinpositionvalue2\"></value>\n" +
-                "<value field=\"pinposition3\">6</value><value field=\"pinpositionvalue3\"></value>\n" +
-                "</row></company-xmlext-query-ret>";
+        String data = """
+                <company-xmlext-query-ret><row><value field="RetCode">LIS_OK</value>
+                <value field="RetCodeExtension"></value><value field="alias"></value>
+                <value field="positioncount"></value><value field="invalidpincount">0</value>
+                <value field="pinposition1">1</value><value field="pinpositionvalue1"></value>
+                <value field="pinposition2">5</value><value field="pinpositionvalue2"></value>
+                <value field="pinposition3">6</value><value field="pinpositionvalue3"></value>
+                </row></company-xmlext-query-ret>""";
         result.setResponseData(data, null);
         result.setResponseHeaders("Header1: Value1\nHeader2: Value2");
         result.setResponseCode("abcd");
diff --git a/src/components/src/test/java/org/apache/jmeter/extractor/TestXPathExtractor.java b/src/components/src/test/java/org/apache/jmeter/extractor/TestXPathExtractor.java
index 9cf66000d5..15ebb4ed25 100644
--- a/src/components/src/test/java/org/apache/jmeter/extractor/TestXPathExtractor.java
+++ b/src/components/src/test/java/org/apache/jmeter/extractor/TestXPathExtractor.java
@@ -317,7 +317,7 @@ public class TestXPathExtractor {
         assertEquals("0", vars.get(VAL_NAME_NR));
     }
 
-    private void assertContains(String value, String substring, String message) {
+    private static void assertContains(String value, String substring, String message) {
         assertTrue(value.contains(substring), () -> message + ": " + value + " should contain " + substring);
     }
 }
diff --git a/src/components/src/test/java/org/apache/jmeter/extractor/json/jmespath/TestJMESPathExtractor.java b/src/components/src/test/java/org/apache/jmeter/extractor/json/jmespath/TestJMESPathExtractor.java
index 0cce79b990..2a063f6834 100644
--- a/src/components/src/test/java/org/apache/jmeter/extractor/json/jmespath/TestJMESPathExtractor.java
+++ b/src/components/src/test/java/org/apache/jmeter/extractor/json/jmespath/TestJMESPathExtractor.java
@@ -72,10 +72,16 @@ class TestJMESPathExtractor {
         return Stream.of(
             Arguments.of("[\"one\"]", "[*]", "one", "1"),
             Arguments.of("{\"a\": {\"b\": {\"c\": {\"d\": \"value\"}}}}", "a.b.c.d", "value", "1"),
-            Arguments.of("{\r\n" + "  \"people\": [\r\n" + "    {\"first\": \"James\", \"last\": \"d\"},\r\n"
-                    + "    {\"first\": \"Jacob\", \"last\": \"e\"},\r\n"
-                    + "    {\"first\": \"Jayden\", \"last\": \"f\"},\r\n" + "    {\"missing\": \"different\"}\r\n"
-                    + "  ],\r\n" + "  \"foo\": {\"bar\": \"baz\"}\r\n" + "}", "people[2]",
+            Arguments.of("""
+                            {\r
+                              "people": [\r
+                                {"first": "James", "last": "d"},\r
+                                {"first": "Jacob", "last": "e"},\r
+                                {"first": "Jayden", "last": "f"},\r
+                                {"missing": "different"}\r
+                              ],\r
+                              "foo": {"bar": "baz"}\r
+                            }""", "people[2]",
                     "{\"first\":\"Jayden\",\"last\":\"f\"}",
                     "1")
         );
@@ -93,7 +99,7 @@ class TestJMESPathExtractor {
         testOneMatchOnAllExtractedValues(false, data, jmesPath, expectedResult, expectedMatchNumber);
     }
 
-    private void testOneMatchOnAllExtractedValues(boolean fromVars, String data, String jmesPath, String expectedResult, String expectedMatchNumber) {
+    private static void testOneMatchOnAllExtractedValues(boolean fromVars, String data, String jmesPath, String expectedResult, String expectedMatchNumber) {
         JMeterVariables vars = new JMeterVariables();
         SampleResult sampleResult = new SampleResult();
         JMESPathExtractor processor = setupProcessor(vars, sampleResult, data, fromVars, "-1");
@@ -112,10 +118,16 @@ class TestJMESPathExtractor {
         return Stream.of(
             Arguments.of("[\"one\", \"two\"]", "[*]", new String[] {"one", "two"}, "2"),
             Arguments.of("[\"a\", \"b\", \"c\", \"d\", \"e\", \"f\"]", "[0:3]", new String[] {"a", "b","c"}, "3"),
-            Arguments.of("{\r\n" + "  \"people\": [\r\n" + "    {\"first\": \"James\", \"last\": \"d\"},\r\n"
-                    + "    {\"first\": \"Jacob\", \"last\": \"e\"},\r\n"
-                    + "    {\"first\": \"Jayden\", \"last\": \"f\"},\r\n" + "    {\"missing\": \"different\"}\r\n"
-                    + "  ],\r\n" + "  \"foo\": {\"bar\": \"baz\"}\r\n" + "}", "people[:2].first", new String[] {"James", "Jacob"}, "2")
+            Arguments.of("""
+                    {\r
+                      "people": [\r
+                        {"first": "James", "last": "d"},\r
+                        {"first": "Jacob", "last": "e"},\r
+                        {"first": "Jayden", "last": "f"},\r
+                        {"missing": "different"}\r
+                      ],\r
+                      "foo": {"bar": "baz"}\r
+                    }""", "people[:2].first", new String[] {"James", "Jacob"}, "2")
         );
     }
 
@@ -131,7 +143,7 @@ class TestJMESPathExtractor {
         testMultipleMatchesOnAllExtractedValues(false, data, jmesPath, expectedResults, expectedMatchNumber);
     }
 
-    private void testMultipleMatchesOnAllExtractedValues(boolean fromVars, String data, String jmesPath, String[] expectedResults, String expectedMatchNumber) {
+    private static void testMultipleMatchesOnAllExtractedValues(boolean fromVars, String data, String jmesPath, String[] expectedResults, String expectedMatchNumber) {
         SampleResult sampleResult = new SampleResult();
         JMeterVariables vars = new JMeterVariables();
         JMESPathExtractor processor = setupProcessor(vars, sampleResult, data, fromVars, "-1");
@@ -145,11 +157,16 @@ class TestJMESPathExtractor {
         assertEquals(expectedMatchNumber, vars.get(REFERENCE_NAME_MATCH_NUMBER));
     }
 
-    private static final String TEST_DATA = "{\r\n" + "  \"people\": [\r\n" + "    {\"first\": \"James\", \"last\": \"d\", \"age\":10},\r\n"
-            + "    {\"first\": \"Jacob\", \"last\": \"e\", \"age\":20},\r\n"
-            + "    {\"first\": \"Jayden\", \"last\": \"f\", \"age\":30},\r\n"
-            + "    {\"missing\": \"different\"}\r\n" + "  ],\r\n" + "  \"foo\": {\"bar\": \"baz\"}\r\n"
-            + "}";
+    private static final String TEST_DATA = """
+            {\r
+              "people": [\r
+                {"first": "James", "last": "d", "age":10},\r
+                {"first": "Jacob", "last": "e", "age":20},\r
+                {"first": "Jayden", "last": "f", "age":30},\r
+                {"missing": "different"}\r
+              ],\r
+              "foo": {"bar": "baz"}\r
+            }""";
 
     private static Stream<Arguments> dataMatchNumberMoreThanZero() {
         return Stream.of(
@@ -175,8 +192,8 @@ class TestJMESPathExtractor {
         testMatchNumberMoreThanZeroOn1ExtractedValue(false, data, jmesPath, matchNumber, expectedResult, expectedMatchNumber);
     }
 
-    private void testMatchNumberMoreThanZeroOn1ExtractedValue(boolean fromVars, String data, String jmesPath,
-            String matchNumber, String expectedResult, String expectedMatchNumber) {
+    private static void testMatchNumberMoreThanZeroOn1ExtractedValue(boolean fromVars, String data, String jmesPath,
+                                                                     String matchNumber, String expectedResult, String expectedMatchNumber) {
         SampleResult sampleResult = new SampleResult();
         JMeterVariables vars = new JMeterVariables();
         JMESPathExtractor processor = setupProcessor(vars, sampleResult, data, fromVars, "1");
@@ -239,7 +256,7 @@ class TestJMESPathExtractor {
     }
 
     private static Stream<Arguments> dataSourceVarOrResponse() {
-        return Stream.of(Arguments.of(Boolean.TRUE), Arguments.of(Boolean.FALSE));
+        return Stream.of(Arguments.of(true), Arguments.of(false));
     }
 
     @ParameterizedTest
diff --git a/src/components/src/test/java/org/apache/jmeter/timers/SyncTimerTest.java b/src/components/src/test/java/org/apache/jmeter/timers/SyncTimerTest.java
index ceee196ba5..88a4a01e6e 100644
--- a/src/components/src/test/java/org/apache/jmeter/timers/SyncTimerTest.java
+++ b/src/components/src/test/java/org/apache/jmeter/timers/SyncTimerTest.java
@@ -86,14 +86,14 @@ public class SyncTimerTest {
             timer::delay);
     }
 
-    private long timeDelay(SyncTimer timer) {
+    private static long timeDelay(SyncTimer timer) {
         long start = System.currentTimeMillis();
         timer.delay();
         long duration = System.currentTimeMillis() - start;
         return duration;
     }
 
-    private void setupScheduledThread(long schedulerDuration) {
+    private static void setupScheduledThread(long schedulerDuration) {
         ListedHashTree hashTree = new ListedHashTree();
         hashTree.add(new LoopController());
         JMeterThread thread = new JMeterThread(hashTree, null, null);
diff --git a/src/components/src/test/java/org/apache/jmeter/visualizers/TestSampleCompareTo.java b/src/components/src/test/java/org/apache/jmeter/visualizers/TestSampleCompareTo.java
index 9e4fb3b4b6..c23950ca12 100644
--- a/src/components/src/test/java/org/apache/jmeter/visualizers/TestSampleCompareTo.java
+++ b/src/components/src/test/java/org/apache/jmeter/visualizers/TestSampleCompareTo.java
@@ -46,7 +46,7 @@ class TestSampleCompareTo {
         assertEquals(compareResult, sample(thisCount).compareTo(sample(otherCount)));
     }
 
-    private Sample sample(long count) {
+    private static Sample sample(long count) {
         return new Sample("dummy", 0L, 0L, 0L, 0L, 0L, 0.0, 0L, true, count, 0L);
     }
 
diff --git a/src/components/src/test/java/org/apache/jmeter/visualizers/backend/SamplerMetricFixedModeTest.java b/src/components/src/test/java/org/apache/jmeter/visualizers/backend/SamplerMetricFixedModeTest.java
index 8fdac49e5e..f174d2582b 100644
--- a/src/components/src/test/java/org/apache/jmeter/visualizers/backend/SamplerMetricFixedModeTest.java
+++ b/src/components/src/test/java/org/apache/jmeter/visualizers/backend/SamplerMetricFixedModeTest.java
@@ -78,7 +78,7 @@ public class SamplerMetricFixedModeTest {
     }
 
     @Test
-    public void checkErrorsDetailStat() {
+    public static void checkErrorsDetailStat() {
         SamplerMetric metric = new SamplerMetric();
         metric.add(createSampleResult("400", "bad request"));
         metric.add(createSampleResult("400", "Bad Request "));
@@ -89,7 +89,7 @@ public class SamplerMetricFixedModeTest {
         assertEquals(1, metric.getErrors().get(error), 0.0, "Count for '500 - Internal Server Error' error ");
     }
 
-    private SampleResult createSampleResult(boolean success) {
+    private static SampleResult createSampleResult(boolean success) {
         SampleResult result = new SampleResult();
         result.setSuccessful(success);
         result.setSampleCount(1);
@@ -101,14 +101,14 @@ public class SamplerMetricFixedModeTest {
         return result;
     }
 
-    private SampleResult createSampleResult(String errorCode, String errorMessage) {
+    private static SampleResult createSampleResult(String errorCode, String errorMessage) {
         SampleResult result = createSampleResult(false);
         result.setResponseCode(errorCode);
         result.setResponseMessage(errorMessage);
         return result;
     }
 
-    private SampleResult createSampleResultWithSubresults(boolean success) {
+    private static SampleResult createSampleResultWithSubresults(boolean success) {
         SampleResult result = new SampleResult();
         result.sampleStart();
         result.setSampleCount(1);
@@ -124,10 +124,10 @@ public class SamplerMetricFixedModeTest {
     }
 
     @Test
-    public void checkAddCumulatedOk() throws Exception {
+    public static void checkAddCumulatedOk() throws Exception {
         SamplerMetric metric = new SamplerMetric();
         SampleResult sample = createSampleResultWithSubresults(true);
-        assertEquals(Boolean.TRUE, TransactionController.isFromTransactionController(sample), "We are recognized as a TransactionController made sample");
+        assertEquals(true, TransactionController.isFromTransactionController(sample), "We are recognized as a TransactionController made sample");
         metric.addCumulated(sample);
         assertEquals(DEFAULT_ELAPSED_TIME, metric.getOkMaxTime(), ALLOWED_DELTA, "Before reset  ok.max");
         assertEquals(DEFAULT_ELAPSED_TIME, metric.getAllMaxTime(), ALLOWED_DELTA, "Before reset all.max");
@@ -145,10 +145,10 @@ public class SamplerMetricFixedModeTest {
     }
 
     @Test
-    public void checkAddCumulatedKo() throws Exception {
+    public static void checkAddCumulatedKo() throws Exception {
         SamplerMetric metric = new SamplerMetric();
         SampleResult sample = createSampleResultWithSubresults(false);
-        assertEquals(Boolean.TRUE, TransactionController.isFromTransactionController(sample), "We are recognized as a TransactionController made sample");
+        assertEquals(true, TransactionController.isFromTransactionController(sample), "We are recognized as a TransactionController made sample");
         metric.addCumulated(sample);
         assertEquals(DEFAULT_ELAPSED_TIME, metric.getKoMaxTime(), ALLOWED_DELTA, "Before reset  ko.max");
         assertEquals(DEFAULT_ELAPSED_TIME, metric.getAllMaxTime(), ALLOWED_DELTA, "Before reset all.max");
diff --git a/src/components/src/test/java/org/apache/jmeter/visualizers/backend/SamplerMetricTimedModeTest.java b/src/components/src/test/java/org/apache/jmeter/visualizers/backend/SamplerMetricTimedModeTest.java
index 42c3835f7a..3cb898f1f7 100644
--- a/src/components/src/test/java/org/apache/jmeter/visualizers/backend/SamplerMetricTimedModeTest.java
+++ b/src/components/src/test/java/org/apache/jmeter/visualizers/backend/SamplerMetricTimedModeTest.java
@@ -78,7 +78,7 @@ public class SamplerMetricTimedModeTest {
         assertEquals(0, metric.getReceivedBytes(), 0.0, "After reset received bytes");
     }
 
-    private SampleResult createSampleResult(boolean success) {
+    private static SampleResult createSampleResult(boolean success) {
         SampleResult result = new SampleResult();
         result.setSuccessful(success);
         result.setSampleCount(1);
@@ -90,7 +90,7 @@ public class SamplerMetricTimedModeTest {
         return result;
     }
 
-    private SampleResult createSampleResultWithSubresults(boolean success) {
+    private static SampleResult createSampleResultWithSubresults(boolean success) {
         SampleResult result = new SampleResult();
         result.sampleStart();
         result.setSampleCount(1);
@@ -106,10 +106,10 @@ public class SamplerMetricTimedModeTest {
     }
 
     @Test
-    public void checkAddCumulatedOk() throws Exception {
+    public static void checkAddCumulatedOk() throws Exception {
         SamplerMetric metric = new SamplerMetric();
         SampleResult sample = createSampleResultWithSubresults(true);
-        assertEquals(Boolean.TRUE, TransactionController.isFromTransactionController(sample), "We are recognized as a TransactionController made sample");
+        assertEquals(true, TransactionController.isFromTransactionController(sample), "We are recognized as a TransactionController made sample");
         metric.addCumulated(sample);
         assertEquals(DEFAULT_ELAPSED_TIME, metric.getOkMaxTime(), ALLOWED_DELTA, "Before reset  ok.max");
         assertEquals(DEFAULT_ELAPSED_TIME, metric.getAllMaxTime(), ALLOWED_DELTA, "Before reset all.max");
@@ -127,10 +127,10 @@ public class SamplerMetricTimedModeTest {
     }
 
     @Test
-    public void checkAddCumulatedKo() throws Exception {
+    public static void checkAddCumulatedKo() throws Exception {
         SamplerMetric metric = new SamplerMetric();
         SampleResult sample = createSampleResultWithSubresults(false);
-        assertEquals(Boolean.TRUE, TransactionController.isFromTransactionController(sample), "We are recognized as a TransactionController made sample");
+        assertEquals(true, TransactionController.isFromTransactionController(sample), "We are recognized as a TransactionController made sample");
         metric.addCumulated(sample);
         assertEquals(DEFAULT_ELAPSED_TIME, metric.getKoMaxTime(), ALLOWED_DELTA, "Before reset  ko.max");
         assertEquals(DEFAULT_ELAPSED_TIME, metric.getAllMaxTime(), ALLOWED_DELTA, "Before reset all.max");
diff --git a/src/components/src/test/java/org/apache/jmeter/visualizers/backend/influxdb/HttpMetricsSenderTest.java b/src/components/src/test/java/org/apache/jmeter/visualizers/backend/influxdb/HttpMetricsSenderTest.java
index d5ae6d951d..6097da5456 100644
--- a/src/components/src/test/java/org/apache/jmeter/visualizers/backend/influxdb/HttpMetricsSenderTest.java
+++ b/src/components/src/test/java/org/apache/jmeter/visualizers/backend/influxdb/HttpMetricsSenderTest.java
@@ -45,7 +45,7 @@ import com.github.tomakehurst.wiremock.matching.StringValuePattern;
 public class HttpMetricsSenderTest {
     private static final String API_URL = "/api/v2/write";
 
-    private MappingBuilder influxRequest(CountDownLatch latch) {
+    private static MappingBuilder influxRequest(CountDownLatch latch) {
         return WireMock.post(API_URL)
                 .willReturn(WireMock.aResponse().withStatus(HttpURLConnection.HTTP_NO_CONTENT))
                 .withServeEventListener(ServeEventListener.RequestPhase.AFTER_COMPLETE, "countdown", Parameters.one("latch", latch));
@@ -78,7 +78,7 @@ public class HttpMetricsSenderTest {
         assertAuthHeader(server, WireMock.equalTo("Token my-token"));
     }
 
-    private void setupSenderAndSendMetric(String influxdbUrl, String influxDBToken) throws Exception {
+    private static void setupSenderAndSendMetric(String influxdbUrl, String influxDBToken) throws Exception {
         HttpMetricsSender metricsSender = new HttpMetricsSender();
         metricsSender.setup(influxdbUrl, influxDBToken);
         metricsSender.addMetric("measurement", ",location=west", "size=10");
@@ -86,7 +86,7 @@ public class HttpMetricsSenderTest {
         metricsSender.destroy();
     }
 
-    private void assertAuthHeader(WireMockServer server, StringValuePattern authHeader) {
+    private static void assertAuthHeader(WireMockServer server, StringValuePattern authHeader) {
         server.verify(1, RequestPatternBuilder
                 .newRequestPattern(RequestMethod.POST, WireMock.urlEqualTo(API_URL))
                 .withRequestBody(WireMock.matching("measurement,location=west size=10 \\d{19}\\s*"))
diff --git a/src/core/src/main/java/org/apache/jmeter/JMeter.java b/src/core/src/main/java/org/apache/jmeter/JMeter.java
index 70d790b3c3..c4a7a8c1f7 100644
--- a/src/core/src/main/java/org/apache/jmeter/JMeter.java
+++ b/src/core/src/main/java/org/apache/jmeter/JMeter.java
@@ -754,7 +754,7 @@ public class JMeter implements JMeterPlugin {
 
         // Add local JMeter properties, if the file is found
         String userProp = JMeterUtils.getPropDefault("user.properties",""); //$NON-NLS-1$
-        if (userProp.length() > 0){ //$NON-NLS-1$
+        if (!userProp.isEmpty()) {
             File file = JMeterUtils.findFile(userProp);
             if (file.canRead()){
                 try (FileInputStream fis = new FileInputStream(file)){
@@ -770,7 +770,7 @@ public class JMeter implements JMeterPlugin {
 
         // Add local system properties, if the file is found
         String sysProp = JMeterUtils.getPropDefault("system.properties",""); //$NON-NLS-1$
-        if (sysProp.length() > 0){
+        if (!sysProp.isEmpty()) {
             File file = JMeterUtils.findFile(sysProp);
             if (file.canRead()) {
                 try (FileInputStream fis = new FileInputStream(file)){
@@ -791,105 +791,99 @@ public class JMeter implements JMeterPlugin {
             String value = option.getArgument(1);
 
             switch (option.getDescriptor().getId()) {
-
-            // Should not have any text arguments
-            case CLOption.TEXT_ARGUMENT:
-                throw new IllegalArgumentException("Unknown arg: " + option.getArgument());
-
-            case PROPFILE2_OPT: // Bug 33920 - allow multiple props
-                log.info("Loading additional properties from: {}", name);
-                try (FileInputStream fis = new FileInputStream(new File(name))){
-                    Properties tmp = new Properties();
-                    tmp.load(fis);
-                    jmeterProps.putAll(tmp);
-                } catch (FileNotFoundException e) { // NOSONAR
-                    log.warn("Can't find additional property file: {}", name, e);
-                } catch (IOException e) { // NOSONAR
-                    log.warn("Error loading additional property file: {}", name, e);
+                // Should not have any text arguments
+                case CLOption.TEXT_ARGUMENT ->
+                        throw new IllegalArgumentException("Unknown arg: " + option.getArgument());
+                case PROPFILE2_OPT -> {
+                    log.info("Loading additional properties from: {}", name);
+                    try (FileInputStream fis = new FileInputStream(name)) {
+                        Properties tmp = new Properties();
+                        tmp.load(fis);
+                        jmeterProps.putAll(tmp);
+                    } catch (FileNotFoundException e) { // NOSONAR
+                        log.warn("Can't find additional property file: {}", name, e);
+                    } catch (IOException e) { // NOSONAR
+                        log.warn("Error loading additional property file: {}", name, e);
+                    }
                 }
-                break;
-            case SYSTEM_PROPFILE:
-                log.info("Setting System properties from file: {}", name);
-                try (FileInputStream fis = new FileInputStream(new File(name))){
-                    System.getProperties().load(fis);
-                } catch (IOException e) { // NOSONAR
-                    if (log.isWarnEnabled()) {
-                        log.warn("Cannot find system property file. {}", e.getLocalizedMessage());
+                case SYSTEM_PROPFILE -> {
+                    log.info("Setting System properties from file: {}", name);
+                    try (FileInputStream fis = new FileInputStream(name)) {
+                        System.getProperties().load(fis);
+                    } catch (IOException e) { // NOSONAR
+                        if (log.isWarnEnabled()) {
+                            log.warn("Cannot find system property file. {}", e.getLocalizedMessage());
+                        }
                     }
                 }
-                break;
-            case SYSTEM_PROPERTY:
-                if (value.length() > 0) { // Set it
-                    log.info("Setting System property: {}={}", name, value);
-                    System.getProperties().setProperty(name, value);
-                } else { // Reset it
-                    log.warn("Removing System property: {}", name);
-                    System.getProperties().remove(name);
+                case SYSTEM_PROPERTY -> {
+                    if (!value.isEmpty()) { // Set it
+                        log.info("Setting System property: {}={}", name, value);
+                        System.getProperties().setProperty(name, value);
+                    } else { // Reset it
+                        log.warn("Removing System property: {}", name);
+                        System.getProperties().remove(name);
+                    }
                 }
-                break;
-            case JMETER_PROPERTY:
-                if (value.length() > 0) { // Set it
-                    log.info("Setting JMeter property: {}={}", name, value);
-                    jmeterProps.setProperty(name, value);
-                } else { // Reset it
-                    log.warn("Removing JMeter property: {}", name);
-                    jmeterProps.remove(name);
+                case JMETER_PROPERTY -> {
+                    if (!value.isEmpty()) { // Set it
+                        log.info("Setting JMeter property: {}={}", name, value);
+                        jmeterProps.setProperty(name, value);
+                    } else { // Reset it
+                        log.warn("Removing JMeter property: {}", name);
+                        jmeterProps.remove(name);
+                    }
                 }
-                break;
-            case JMETER_GLOBAL_PROP:
-                if (value.length() > 0) { // Set it
-                    log.info("Setting Global property: {}={}", name, value);
-                    remoteProps.setProperty(name, value);
-                } else {
-                    File propFile = new File(name);
-                    if (propFile.canRead()) {
-                        log.info("Setting Global properties from the file {}", name);
-                        try (FileInputStream fis = new FileInputStream(propFile)){
-                            remoteProps.load(fis);
-                        } catch (FileNotFoundException e) { // NOSONAR
-                            if (log.isWarnEnabled()) {
-                                log.warn("Could not find properties file: {}", e.getLocalizedMessage());
-                            }
-                        } catch (IOException e) { // NOSONAR
-                            if (log.isWarnEnabled()) {
-                                log.warn("Could not load properties file: {}", e.getLocalizedMessage());
+                case JMETER_GLOBAL_PROP -> {
+                    if (!value.isEmpty()) { // Set it
+                        log.info("Setting Global property: {}={}", name, value);
+                        remoteProps.setProperty(name, value);
+                    } else {
+                        File propFile = new File(name);
+                        if (propFile.canRead()) {
+                            log.info("Setting Global properties from the file {}", name);
+                            try (FileInputStream fis = new FileInputStream(propFile)) {
+                                remoteProps.load(fis);
+                            } catch (FileNotFoundException e) { // NOSONAR
+                                if (log.isWarnEnabled()) {
+                                    log.warn("Could not find properties file: {}", e.getLocalizedMessage());
+                                }
+                            } catch (IOException e) { // NOSONAR
+                                if (log.isWarnEnabled()) {
+                                    log.warn("Could not load properties file: {}", e.getLocalizedMessage());
+                                }
                             }
                         }
                     }
                 }
-                break;
-            case LOGLEVEL:
-                if (value.length() > 0) { // Set category
-                    log.info("LogLevel: {}={}", name, value);
-                    final Level logLevel = Level.getLevel(value);
-                    if (logLevel != null) {
-                        String loggerName = name;
-                        if (name.startsWith("jmeter") || name.startsWith("jorphan")) {
-                            loggerName = PACKAGE_PREFIX + name;
+                case LOGLEVEL -> {
+                    if (!value.isEmpty()) { // Set category
+                        log.info("LogLevel: {}={}", name, value);
+                        final Level logLevel = Level.getLevel(value);
+                        if (logLevel != null) {
+                            String loggerName = name;
+                            if (name.startsWith("jmeter") || name.startsWith("jorphan")) {
+                                loggerName = PACKAGE_PREFIX + name;
+                            }
+                            Configurator.setAllLevels(loggerName, logLevel);
+                        } else {
+                            log.warn("Invalid log level, '{}' for '{}'.", value, name);
+                        }
+                    } else { // Set root level
+                        log.warn("LogLevel: {}", name);
+                        final Level logLevel = Level.getLevel(name);
+                        if (logLevel != null) {
+                            Configurator.setRootLevel(logLevel);
+                        } else {
+                            log.warn("Invalid log level, '{}', for the root logger.", name);
                         }
-                        Configurator.setAllLevels(loggerName, logLevel);
-                    } else {
-                        log.warn("Invalid log level, '{}' for '{}'.", value, name);
-                    }
-                } else { // Set root level
-                    log.warn("LogLevel: {}", name);
-                    final Level logLevel = Level.getLevel(name);
-                    if (logLevel != null) {
-                        Configurator.setRootLevel(logLevel);
-                    } else {
-                        log.warn("Invalid log level, '{}', for the root logger.", name);
                     }
                 }
-                break;
-            case REMOTE_STOP:
-                remoteStop = true;
-                break;
-            case FORCE_DELETE_RESULT_FILE:
-                deleteResultFile = true;
-                break;
-            default:
+                case REMOTE_STOP -> remoteStop = true;
+                case FORCE_DELETE_RESULT_FILE -> deleteResultFile = true;
+                default -> {
+                }
                 // ignored
-                break;
             }
         }
 
@@ -900,7 +894,7 @@ public class JMeter implements JMeterPlugin {
         jmeterProps.put("jmeter.version", JMeterUtils.getJMeterVersion());
     }
 
-    /*
+    /**
      * Checks for LAST or LASTsuffix.
      * Returns the LAST name with .JMX replaced by suffix.
      */
@@ -974,7 +968,7 @@ public class JMeter implements JMeterPlugin {
 
             Summariser summariser = null;
             String summariserName = JMeterUtils.getPropDefault("summariser.name", "");//$NON-NLS-1$
-            if (summariserName.length() > 0) {
+            if (!summariserName.isEmpty()) {
                 log.info("Creating summariser <{}>", summariserName);
                 println("Creating summariser <" + summariserName + ">");
                 summariser = new Summariser(summariserName);
@@ -1108,8 +1102,7 @@ public class JMeter implements JMeterPlugin {
      */
     private static void pConvertSubTree(HashTree tree) {
         for (Object o : new ArrayList<>(tree.list())) {
-            if (o instanceof TestElement) {
-                TestElement item = (TestElement) o;
+            if (o instanceof TestElement item) {
                 if (item.isEnabled()) {
                     if (item instanceof ReplaceableController) {
                         ReplaceableController rc = ensureReplaceableControllerIsLoaded(item);
@@ -1179,7 +1172,7 @@ public class JMeter implements JMeterPlugin {
         return rc;
     }
 
-    /*
+    /**
      * Listen to test and handle tidyup after non-GUI test completes.
      * If running a remote test, then after waiting a few seconds for listeners to finish files,
      * it calls ClientJMeterEngine.tidyRMI() to deal with the Naming Timer Thread.
@@ -1206,13 +1199,13 @@ public class JMeter implements JMeterPlugin {
          * @param remoteStop
          * @param reportGenerator {@link ReportGenerator}
          */
-        public ListenToTest(RunMode runMode, boolean remoteStop, ReportGenerator reportGenerator) {
+        private ListenToTest(RunMode runMode, boolean remoteStop, ReportGenerator reportGenerator) {
             this.runMode = runMode;
             this.remoteStop = remoteStop;
             this.reportGenerator = reportGenerator;
         }
 
-        public void setStartedRemoteEngines(List<? extends JMeterEngine> engines) {
+        private void setStartedRemoteEngines(List<? extends JMeterEngine> engines) {
             if (runMode != RunMode.REMOTE) {
                 throw new IllegalArgumentException("This method should only be called in RunMode.REMOTE");
             }
@@ -1413,25 +1406,20 @@ public class JMeter implements JMeterPlugin {
                     String command = new String(request.getData(), request.getOffset(), request.getLength(), StandardCharsets.US_ASCII);
                     System.out.println("Command: "+command+" received from "+address);//NOSONAR
                     log.info("Command: {} received from {}", command, address);
-                    switch(command) {
-                        case "StopTestNow" :
-                            for(JMeterEngine engine : engines) {
+                    switch (command) {
+                        case "StopTestNow" -> {
+                            for (JMeterEngine engine : engines) {
                                 engine.stopTest(true);
                             }
-                            break;
-                        case "Shutdown" :
-                            for(JMeterEngine engine : engines) {
+                        }
+                        case "Shutdown" -> {
+                            for (JMeterEngine engine : engines) {
                                 engine.stopTest(false);
                             }
-                            break;
-                        case "HeapDump" :
-                            HeapDumper.dumpHeap();
-                            break;
-                        case "ThreadDump" :
-                            ThreadDumper.threadDump();
-                            break;
-                        default:
-                            System.out.println("Command: "+command+" not recognised ");//NOSONAR
+                        }
+                        case "HeapDump" -> HeapDumper.dumpHeap();
+                        case "ThreadDump" -> ThreadDumper.threadDump();
+                        default -> System.out.println("Command: " + command + " not recognised ");//NOSONAR
                     }
                 }
             }
diff --git a/src/core/src/main/java/org/apache/jmeter/ProxyAuthenticator.java b/src/core/src/main/java/org/apache/jmeter/ProxyAuthenticator.java
index b4154e7dba..8067a6b3e6 100644
--- a/src/core/src/main/java/org/apache/jmeter/ProxyAuthenticator.java
+++ b/src/core/src/main/java/org/apache/jmeter/ProxyAuthenticator.java
@@ -55,12 +55,9 @@ public class ProxyAuthenticator extends Authenticator {
      */
     @Override
     protected PasswordAuthentication getPasswordAuthentication() {
-        switch (getRequestorType()){
-            case PROXY:
-                return new PasswordAuthentication(userName, password);
-            case SERVER:
-                break;
-        }
-        return null;
+        return switch (getRequestorType()) {
+            case PROXY -> new PasswordAuthentication(userName, password);
+            case SERVER -> null;
+        };
     }
 }
diff --git a/src/core/src/main/java/org/apache/jmeter/assertions/CompareAssertionResult.java b/src/core/src/main/java/org/apache/jmeter/assertions/CompareAssertionResult.java
index 2b98617247..f306ef9f93 100644
--- a/src/core/src/main/java/org/apache/jmeter/assertions/CompareAssertionResult.java
+++ b/src/core/src/main/java/org/apache/jmeter/assertions/CompareAssertionResult.java
@@ -63,11 +63,11 @@ public class CompareAssertionResult extends AssertionResult {
         private String baseResult;
         private String secondaryResult;
 
-        public ResultHolder()
+        private ResultHolder()
         {
         }
 
-        public void addToBaseResult(String r)
+        private void addToBaseResult(String r)
         {
             if(baseResult == null)
             {
@@ -79,7 +79,7 @@ public class CompareAssertionResult extends AssertionResult {
             }
         }
 
-        public void addToSecondaryResult(String r)
+        private void addToSecondaryResult(String r)
         {
             if(secondaryResult == null)
             {
diff --git a/src/core/src/main/java/org/apache/jmeter/config/gui/ArgumentsPanel.java b/src/core/src/main/java/org/apache/jmeter/config/gui/ArgumentsPanel.java
index 0c9fd32dba..fc13ca9ec2 100644
--- a/src/core/src/main/java/org/apache/jmeter/config/gui/ArgumentsPanel.java
+++ b/src/core/src/main/java/org/apache/jmeter/config/gui/ArgumentsPanel.java
@@ -293,8 +293,7 @@ public class ArgumentsPanel extends AbstractConfigGui implements ActionListener
     @Override
     public void modifyTestElement(TestElement args) {
         GuiUtils.stopTableEditing(table);
-        if (args instanceof Arguments) {
-            Arguments arguments = (Arguments) args;
+        if (args instanceof Arguments arguments) {
             arguments.clear();
             @SuppressWarnings("unchecked") // only contains Argument (or HTTPArgument)
             Iterator<Argument> modelData = (Iterator<Argument>) tableModel.iterator();
@@ -321,9 +320,9 @@ public class ArgumentsPanel extends AbstractConfigGui implements ActionListener
     @Override
     public void configure(TestElement el) {
         super.configure(el);
-        if (el instanceof Arguments) {
+        if (el instanceof Arguments arguments) {
             tableModel.clearData();
-            for (JMeterProperty jMeterProperty : (Arguments) el) {
+            for (JMeterProperty jMeterProperty : arguments) {
                 Argument arg = (Argument) jMeterProperty.getObjectValue();
                 tableModel.addRow(arg);
             }
diff --git a/src/core/src/main/java/org/apache/jmeter/config/gui/RowDetailDialog.java b/src/core/src/main/java/org/apache/jmeter/config/gui/RowDetailDialog.java
index fef3c25a7e..d24106daf9 100644
--- a/src/core/src/main/java/org/apache/jmeter/config/gui/RowDetailDialog.java
+++ b/src/core/src/main/java/org/apache/jmeter/config/gui/RowDetailDialog.java
@@ -184,8 +184,8 @@ public class RowDetailDialog extends JDialog implements ActionListener, Document
         if (column > 0 || columnCount == 1) {
             if (tableModel.getColumnClass(column).equals(Boolean.class)) {
                 JCheckBox checkBox = new JCheckBox();
-                if (value instanceof Boolean) {
-                    checkBox.setSelected((Boolean) value);
+                if (value instanceof Boolean b) {
+                    checkBox.setSelected(b);
                 }
                 checkBox.addItemListener(this);
                 dataComponents.add(checkBox);
@@ -193,8 +193,8 @@ public class RowDetailDialog extends JDialog implements ActionListener, Document
             } else {
                 JSyntaxTextArea dataArea = JSyntaxTextArea
                         .getInstance(linesPerTextArea, 80);
-                if (value instanceof String) {
-                    dataArea.setInitialText((String) value);
+                if (value instanceof String s) {
+                    dataArea.setInitialText(s);
                 }
                 dataArea.getDocument().addDocumentListener(this);
                 dataComponents.add(dataArea);
@@ -202,8 +202,8 @@ public class RowDetailDialog extends JDialog implements ActionListener, Document
             }
         } else {
             final JTextField nameTF = new JTextField("");
-            if (value instanceof String) {
-                nameTF.setText((String) value);
+            if (value instanceof String s) {
+                nameTF.setText(s);
             }
             nameTF.getDocument().addDocumentListener(this);
             dataComponents.add(nameTF);
@@ -245,14 +245,13 @@ public class RowDetailDialog extends JDialog implements ActionListener, Document
     private void setValues(int selectedRow) {
         for (int i = 0; i < tableModel.getColumnCount(); i++) {
             final JComponent component = dataComponents.get(i);
-            if (component instanceof JTextComponent) {
-                JTextComponent dataArea = (JTextComponent) component;
+            if (component instanceof JTextComponent dataArea) {
                 dataArea.setText((String) tableModel.getValueAt(selectedRow, i));
                 if (dataArea instanceof JSyntaxTextArea) {
                     dataArea.setCaretPosition(0);
                 }
-            } else if (component instanceof JCheckBox) {
-                ((JCheckBox) component).setSelected((Boolean) tableModel.getValueAt(selectedRow, i));
+            } else if (component instanceof JCheckBox jCheckBox) {
+                jCheckBox.setSelected((Boolean) tableModel.getValueAt(selectedRow, i));
             }
         }
         textChanged = false;
@@ -265,10 +264,10 @@ public class RowDetailDialog extends JDialog implements ActionListener, Document
     protected void doUpdate(ActionEvent actionEvent) {
         for (int i = 0; i < tableModel.getColumnCount(); i++) {
             final JComponent component = dataComponents.get(i);
-            if (component instanceof JTextComponent) {
-                tableModel.setValueAt(((JTextComponent) component).getText(), selectedRow, i);
-            } else if (component instanceof JCheckBox) {
-                tableModel.setValueAt(((JCheckBox) component).isSelected(), selectedRow, i);
+            if (component instanceof JTextComponent jTextComponent) {
+                tableModel.setValueAt(jTextComponent.getText(), selectedRow, i);
+            } else if (component instanceof JCheckBox jCheckBox) {
+                tableModel.setValueAt(jCheckBox.isSelected(), selectedRow, i);
             }
         }
         // Change Cancel label to Close
diff --git a/src/core/src/main/java/org/apache/jmeter/control/GenericController.java b/src/core/src/main/java/org/apache/jmeter/control/GenericController.java
index ff88a79315..b4efd777f5 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/GenericController.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/GenericController.java
@@ -179,8 +179,8 @@ public class GenericController extends AbstractTestElement implements Controller
             if (currentElement == null) {
                 returnValue = nextIsNull();
             } else {
-                if (currentElement instanceof Sampler) {
-                    returnValue = nextIsASampler((Sampler) currentElement);
+                if (currentElement instanceof Sampler sampler) {
+                    returnValue = nextIsASampler(sampler);
                 } else { // must be a controller
                     returnValue = nextIsAController((Controller) currentElement);
                 }
@@ -376,11 +376,9 @@ public class GenericController extends AbstractTestElement implements Controller
 
     @Override
     public void addIterationListener(LoopIterationListener lis) {
-        /*
-         * A little hack - add each listener to the start of the list - this
-         * ensures that the thread running the show is the first listener and
-         * can modify certain values before other listeners are called.
-         */
+        // A little hack - add each listener to the start of the list - this
+        // ensures that the thread running the show is the first listener and
+        // can modify certain values before other listeners are called.
         iterationListeners.addFirst(lis);
     }
 
diff --git a/src/core/src/main/java/org/apache/jmeter/control/IfController.java b/src/core/src/main/java/org/apache/jmeter/control/IfController.java
index f19e2cdde1..0927303ffb 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/IfController.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/IfController.java
@@ -122,7 +122,7 @@ public class IfController extends GenericController implements Serializable, Thr
      * Initialization On Demand Holder pattern
      */
     private static class LazyHolder {
-        public static final ScriptEngineManager INSTANCE = new ScriptEngineManager();
+        private static final ScriptEngineManager INSTANCE = new ScriptEngineManager();
     }
 
     /**
@@ -189,17 +189,11 @@ public class IfController extends GenericController implements Serializable, Thr
      */
     private static boolean computeResultFromString(
             String condition, String resultStr) throws Exception {
-        boolean result;
-        switch(resultStr) {
-            case "false":
-                result = false;
-                break;
-            case "true":
-                result = true;
-                break;
-            default:
-                throw new Exception(" BAD CONDITION :: " + condition + " :: expected true or false");
-        }
+        boolean result = switch (resultStr) {
+            case "false" -> false;
+            case "true" -> true;
+            default -> throw new Exception(" BAD CONDITION :: " + condition + " :: expected true or false");
+        };
         log.debug("    >> evaluate Condition -  [{}] results is  [{}]", condition, result);
         return result;
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/control/RunTime.java b/src/core/src/main/java/org/apache/jmeter/control/RunTime.java
index 399ebee4f9..c36a113891 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/RunTime.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/RunTime.java
@@ -110,7 +110,7 @@ public class RunTime extends GenericController implements Serializable {
         startTime = 0;
     }
 
-    /*
+    /**
      * This is needed for OnceOnly to work like other Loop Controllers
      */
     @Override
diff --git a/src/core/src/main/java/org/apache/jmeter/control/TransactionController.java b/src/core/src/main/java/org/apache/jmeter/control/TransactionController.java
index 467aaf2fa3..1f651e2d88 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/TransactionController.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/TransactionController.java
@@ -268,8 +268,7 @@ public class TransactionController extends GenericController implements SampleLi
             // in this case normal workflow doesn't happen, so we need
             // to notify the children of TransactionController and
             // update them with SubSamplerResult
-            if(subSampler instanceof TransactionSampler) {
-                TransactionSampler tc = (TransactionSampler) subSampler;
+            if(subSampler instanceof TransactionSampler tc) {
                 transactionSampler.addSubSamplerResult(tc.getTransactionResult());
             }
             transactionSampler.setTransactionDone();
diff --git a/src/core/src/main/java/org/apache/jmeter/control/gui/IfControllerPanel.java b/src/core/src/main/java/org/apache/jmeter/control/gui/IfControllerPanel.java
index f4a3802727..1b94c963e7 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/gui/IfControllerPanel.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/gui/IfControllerPanel.java
@@ -116,8 +116,7 @@ public class IfControllerPanel extends AbstractControllerGui implements ChangeLi
     @Override
     public void configure(TestElement element) {
         super.configure(element);
-        if (element instanceof IfController) {
-            IfController ifController = (IfController) element;
+        if (element instanceof IfController ifController) {
             theCondition.setText(ifController.getCondition());
             evaluateAll.setSelected(ifController.isEvaluateAll());
             useExpression.setSelected(ifController.isUseExpression());
@@ -141,8 +140,7 @@ public class IfControllerPanel extends AbstractControllerGui implements ChangeLi
     @Override
     public void modifyTestElement(TestElement controller) {
         configureTestElement(controller);
-        if (controller instanceof IfController) {
-            IfController ifController = (IfController) controller;
+        if (controller instanceof IfController ifController) {
             ifController.setCondition(theCondition.getText());
             ifController.setEvaluateAll(evaluateAll.isSelected());
             ifController.setUseExpression(useExpression.isSelected());
diff --git a/src/core/src/main/java/org/apache/jmeter/control/gui/LoopControlPanel.java b/src/core/src/main/java/org/apache/jmeter/control/gui/LoopControlPanel.java
index 8d2e3652ca..c811a63734 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/gui/LoopControlPanel.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/gui/LoopControlPanel.java
@@ -123,8 +123,8 @@ public class LoopControlPanel extends AbstractControllerGui implements ActionLis
     @Override
     public void configure(TestElement element) {
         super.configure(element);
-        if (element instanceof LoopController) {
-            setState(((LoopController) element).getLoopString());
+        if (element instanceof LoopController loopController) {
+            setState(loopController.getLoopString());
         } else {
             setState(1);
         }
@@ -142,11 +142,11 @@ public class LoopControlPanel extends AbstractControllerGui implements ActionLis
     @Override
     public void modifyTestElement(TestElement lc) {
         configureTestElement(lc);
-        if (lc instanceof LoopController) {
-            if (loops.getText().length() > 0) {
-                ((LoopController) lc).setLoops(loops.getText());
+        if (lc instanceof LoopController loopController) {
+            if (!loops.getText().isEmpty()) {
+                loopController.setLoops(loops.getText());
             } else {
-                ((LoopController) lc).setLoops(LoopController.INFINITE_LOOP_COUNT);
+                loopController.setLoops(LoopController.INFINITE_LOOP_COUNT);
             }
         }
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/control/gui/RunTimeGui.java b/src/core/src/main/java/org/apache/jmeter/control/gui/RunTimeGui.java
index 045aab2772..31b9dfcb34 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/gui/RunTimeGui.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/gui/RunTimeGui.java
@@ -89,8 +89,8 @@ public class RunTimeGui extends AbstractControllerGui implements ActionListener
     @Override
     public void configure(TestElement element) {
         super.configure(element);
-        if (element instanceof RunTime) {
-            setState(((RunTime) element).getRuntimeString());
+        if (element instanceof RunTime runTime) {
+            setState(runTime.getRuntimeString());
         } else {
             setState(1);
         }
@@ -108,11 +108,11 @@ public class RunTimeGui extends AbstractControllerGui implements ActionListener
     @Override
     public void modifyTestElement(TestElement lc) {
         configureTestElement(lc);
-        if (lc instanceof RunTime) {
-            if (seconds.getText().length() > 0) {
-                ((RunTime) lc).setRuntime(seconds.getText());
+        if (lc instanceof RunTime runTime) {
+            if (!seconds.getText().isEmpty()) {
+                runTime.setRuntime(seconds.getText());
             } else {
-                ((RunTime) lc).setRuntime(0);
+                runTime.setRuntime(0);
             }
         }
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/control/gui/TestPlanGui.java b/src/core/src/main/java/org/apache/jmeter/control/gui/TestPlanGui.java
index d962b5a082..74b9b0f3fa 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/gui/TestPlanGui.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/gui/TestPlanGui.java
@@ -141,8 +141,7 @@ public class TestPlanGui extends AbstractJMeterGuiComponent {
     @Override
     public void modifyTestElement(TestElement plan) {
         super.modifyTestElement(plan);
-        if (plan instanceof TestPlan) {
-            TestPlan tp = (TestPlan) plan;
+        if (plan instanceof TestPlan tp) {
             // TODO: set expression to TestPlan somehow
             tp.setUserDefinedVariables((Arguments) argsPanel.createTestElement());
             String[] files = browseJar.getFiles();
@@ -185,8 +184,7 @@ public class TestPlanGui extends AbstractJMeterGuiComponent {
     @Override
     public void configure(TestElement el) {
         super.configure(el);
-        if (el instanceof TestPlan) {
-            TestPlan tp = (TestPlan) el;
+        if (el instanceof TestPlan tp) {
             final JMeterProperty udv = tp.getUserDefinedVariablesAsProperty();
             if (udv != null) {
                 argsPanel.configure((Arguments) udv.getObjectValue());
diff --git a/src/core/src/main/java/org/apache/jmeter/control/gui/WhileControllerGui.java b/src/core/src/main/java/org/apache/jmeter/control/gui/WhileControllerGui.java
index 81a8ed2813..0bcca3c2ef 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/gui/WhileControllerGui.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/gui/WhileControllerGui.java
@@ -64,8 +64,8 @@ public class WhileControllerGui extends AbstractControllerGui {
     @Override
     public void configure(TestElement element) {
         super.configure(element);
-        if (element instanceof WhileController) {
-            theCondition.setText(((WhileController) element).getCondition());
+        if (element instanceof WhileController whileController) {
+            theCondition.setText(whileController.getCondition());
         }
 
     }
@@ -86,11 +86,11 @@ public class WhileControllerGui extends AbstractControllerGui {
     @Override
     public void modifyTestElement(TestElement controller) {
         configureTestElement(controller);
-        if (controller instanceof WhileController) {
-            if (theCondition.getText().length() > 0) {
-                ((WhileController) controller).setCondition(theCondition.getText());
+        if (controller instanceof WhileController whileController) {
+            if (!theCondition.getText().isEmpty()) {
+                whileController.setCondition(theCondition.getText());
             } else {
-                ((WhileController) controller).setCondition(""); // $NON-NLS-1$
+                whileController.setCondition(""); // $NON-NLS-1$
             }
         }
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/control/gui/WorkBenchGui.java b/src/core/src/main/java/org/apache/jmeter/control/gui/WorkBenchGui.java
index 89b9adfef6..6ff14fd5ad 100644
--- a/src/core/src/main/java/org/apache/jmeter/control/gui/WorkBenchGui.java
+++ b/src/core/src/main/java/org/apache/jmeter/control/gui/WorkBenchGui.java
@@ -95,8 +95,7 @@ public class WorkBenchGui extends AbstractJMeterGuiComponent {
     @SuppressWarnings("deprecation")
     public void configure(TestElement el) {
         super.configure(el);
-        if (el instanceof org.apache.jmeter.testelement.WorkBench) {
-            org.apache.jmeter.testelement.WorkBench tp = (org.apache.jmeter.testelement.WorkBench) el;
+        if (el instanceof org.apache.jmeter.testelement.WorkBench tp) {
             saveWorkBench.setSelected(tp.getSaveWorkBench());
         }
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/ClientJMeterEngine.java b/src/core/src/main/java/org/apache/jmeter/engine/ClientJMeterEngine.java
index 030be3b94e..0d70116d03 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/ClientJMeterEngine.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/ClientJMeterEngine.java
@@ -70,10 +70,8 @@ public class ClientJMeterEngine implements JMeterEngine {
                port,
                RmiUtils.createClientSocketFactory());
         Remote remobj = registry.lookup(name);
-        if (remobj instanceof RemoteJMeterEngine){
-            final RemoteJMeterEngine rje = (RemoteJMeterEngine) remobj;
-            if (remobj instanceof RemoteObject){
-                RemoteObject robj = (RemoteObject) remobj;
+        if (remobj instanceof RemoteJMeterEngine rje){
+            if (remobj instanceof RemoteObject robj){
                 System.out.println("Using remote object: "+robj.getRef().remoteToString()); // NOSONAR
             }
             return rje;
@@ -140,11 +138,8 @@ public class ClientJMeterEngine implements JMeterEngine {
         String methodName="unknown";
         try {
             JMeterContextService.startTest();
-            /*
-             * Add fix for Deadlocks, see:
-             *
-             * See https://bz.apache.org/bugzilla/show_bug.cgi?id=48350
-            */
+            // Add fix for Deadlocks, see:
+            // See https://bz.apache.org/bugzilla/show_bug.cgi?id=48350
             File baseDirRelative = FileServer.getFileServer().getBaseDirRelative();
             String scriptName = FileServer.getFileServer().getScriptName();
             synchronized(LOCK)
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/ConvertListeners.java b/src/core/src/main/java/org/apache/jmeter/engine/ConvertListeners.java
index a59372f030..0cb2a0616d 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/ConvertListeners.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/ConvertListeners.java
@@ -53,8 +53,8 @@ public class ConvertListeners implements HashTreeTraverser {
     @Override
     public void addNode(Object node, HashTree subTree) {
         for (Object item : subTree.list()) {
-            if (item instanceof AbstractThreadGroup && log.isDebugEnabled()) {
-                log.debug("num threads = {}", ((AbstractThreadGroup) item).getNumThreads());
+            if (item instanceof AbstractThreadGroup abstractThreadGroup && log.isDebugEnabled()) {
+                log.debug("num threads = {}", abstractThreadGroup.getNumThreads());
             }
             if (item instanceof Remoteable) {
                 if (item instanceof RemoteThreadsListenerTestElement){
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/PreCompiler.java b/src/core/src/main/java/org/apache/jmeter/engine/PreCompiler.java
index 389dd3cc95..bae46ced74 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/PreCompiler.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/PreCompiler.java
@@ -72,32 +72,32 @@ public class PreCompiler implements HashTreeTraverser {
                 }
             }
 
-            if (node instanceof TestPlan) {
-                this.clientSideVariables = createVars((TestPlan)node);
+            if (node instanceof TestPlan testPlan) {
+                this.clientSideVariables = createVars(testPlan);
             }
 
-            if (node instanceof Arguments) {
+            if (node instanceof Arguments arguments) {
                 // Don't store User Defined Variables in the context for client side
-                Map<String, String> args = createArgumentsMap((Arguments) node);
+                Map<String, String> args = createArgumentsMap(arguments);
                 clientSideVariables.putAll(args);
             }
 
         } else {
-            if(node instanceof TestElement) {
+            if(node instanceof TestElement testElement) {
                 try {
-                    replacer.replaceValues((TestElement) node);
+                    replacer.replaceValues(testElement);
                 } catch (InvalidVariableException e) {
-                    log.error("invalid variables in node {}", ((TestElement)node).getName(), e);
+                    log.error("invalid variables in node {}", testElement.getName(), e);
                 }
             }
 
-            if (node instanceof TestPlan) {
-                JMeterVariables vars = createVars((TestPlan)node);
+            if (node instanceof TestPlan testPlan) {
+                JMeterVariables vars = createVars(testPlan);
                 JMeterContextService.getContext().setVariables(vars);
             }
 
-            if (node instanceof Arguments) {
-                Map<String, String> args = createArgumentsMap((Arguments) node);
+            if (node instanceof Arguments arguments) {
+                Map<String, String> args = createArgumentsMap(arguments);
                 JMeterContextService.getContext().getVariables().putAll(args);
             }
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/RemoteJMeterEngineImpl.java b/src/core/src/main/java/org/apache/jmeter/engine/RemoteJMeterEngineImpl.java
index 89feca7539..3dd632f9b9 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/RemoteJMeterEngineImpl.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/RemoteJMeterEngineImpl.java
@@ -184,10 +184,6 @@ public final class RemoteJMeterEngineImpl extends java.rmi.server.UnicastRemoteO
         log.info("... stopped");
     }
 
-    /*
-     * Called by:
-     * - ClientJMeterEngine.exe() which is called on remoteStop
-     */
     @Override
     public void rexit() throws RemoteException {
         log.info("Exiting");
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/StandardJMeterEngine.java b/src/core/src/main/java/org/apache/jmeter/engine/StandardJMeterEngine.java
index 59846b4d3b..a1d302db33 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/StandardJMeterEngine.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/StandardJMeterEngine.java
@@ -76,7 +76,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
     // at any one time so it is not guaranteed to work ...
     private static volatile StandardJMeterEngine engine;
 
-    /*
+    /**
      * Allow functions etc to register for testStopped notification.
      * Only used by the function parser so far.
      * The list is merged with the testListeners and then cleared.
@@ -363,7 +363,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
         /**
          * set the shared engine to null
          */
-        private void resetSingletonEngine() {
+        private static void resetSingletonEngine() {
             StandardJMeterEngine.engine = null; // NOSONAR We cannot make the method static here
         }
 
@@ -402,9 +402,7 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
         log.info("Running the test!");
         running = true;
 
-        /*
-         * Ensure that the sample variables are correctly initialised for each run.
-         */
+        // Ensure that the sample variables are correctly initialised for each run.
         SampleEvent.initSampleVariables();
 
         JMeterContextService.startTest();
@@ -416,10 +414,8 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
             JMeterUtils.reportErrorToUser("Error occurred compiling the tree: - see log file", e);
             return; // no point continuing
         }
-        /*
-         * Notification of test listeners needs to happen after function
-         * replacement, but before setting RunningVersion to true.
-         */
+        // Notification of test listeners needs to happen after function
+        // replacement, but before setting RunningVersion to true.
         var testListeners = new SearchByClass<>(TestStateListener.class); // TL - S&E
         test.traverse(testListeners);
 
@@ -479,11 +475,9 @@ public class StandardJMeterEngine implements JMeterEngine, Runnable {
 
         groups.clear(); // The groups have all completed now
 
-        /*
-         * Here's where the test really starts. Run a Full GC now: it's no harm
-         * at all (just delays test start by a tiny amount) and hitting one too
-         * early in the test can impair results for short tests.
-         */
+        // Here's where the test really starts. Run a Full GC now: it's no harm
+        // at all (just delays test start by a tiny amount) and hitting one too
+        // early in the test can impair results for short tests.
         JMeterUtils.helpGC();
 
         JMeterContextService.getContext().setSamplingStarted(true);
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/TreeCloner.java b/src/core/src/main/java/org/apache/jmeter/engine/TreeCloner.java
index fddc404ab1..82918cf72c 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/TreeCloner.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/TreeCloner.java
@@ -69,11 +69,11 @@ public class TreeCloner implements HashTreeTraverser {
      * @return Object node (clone or not)
      */
     protected Object addNodeToTree(Object node) {
-        if ( (node instanceof TestElement) // Check can cast for clone
+        if ( (node instanceof TestElement testElement) // Check can cast for clone
            // Don't clone NoThreadClone unless honourNoThreadClone == false
           && !(honourNoThreadClone && node instanceof NoThreadClone)
         ) {
-            Object newNode = ((TestElement) node).clone();
+            Object newNode = testElement.clone();
             newTree.add(objects, newNode);
             return newNode;
         } else {
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/TurnElementsOn.java b/src/core/src/main/java/org/apache/jmeter/engine/TurnElementsOn.java
index 7bf4b5d7f7..71127c13db 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/TurnElementsOn.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/TurnElementsOn.java
@@ -32,8 +32,8 @@ public class TurnElementsOn implements HashTreeTraverser {
      */
     @Override
     public void addNode(Object node, HashTree subTree) {
-        if (node instanceof TestElement && !(node instanceof TestPlan)) {
-            ((TestElement) node).setRunningVersion(true);
+        if (node instanceof TestElement testElement && !(node instanceof TestPlan)) {
+            testElement.setRunningVersion(true);
         }
 
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/util/CompoundVariable.java b/src/core/src/main/java/org/apache/jmeter/engine/util/CompoundVariable.java
index 5a9b902457..15ceb30800 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/util/CompoundVariable.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/util/CompoundVariable.java
@@ -78,7 +78,7 @@ public class CompoundVariable implements Function {
                     new LogAndIgnoreServiceLoadExceptionHandler(log)
             )) {
                 String referenceKey = function.getReferenceKey();
-                if (referenceKey.length() > 0) { // ignore self
+                if (!referenceKey.isEmpty()) { // ignore self
                     functions.put(referenceKey, function.getClass());
                 }
             }
@@ -135,15 +135,15 @@ public class CompoundVariable implements Function {
 
         StringBuilder results = new StringBuilder();
         for (Object item : compiledComponents) {
-            if (item instanceof Function) {
+            if (item instanceof Function function) {
                 try {
-                    results.append(((Function) item).execute(previousResult, currentSampler));
+                    results.append(function.execute(previousResult, currentSampler));
                 } catch (InvalidVariableException e) {
                     // TODO should level be more than debug ?
                     log.debug("Invalid variable: {}", item, e);
                 }
-            } else if (item instanceof SimpleVariable) {
-                results.append(((SimpleVariable) item).toString());
+            } else if (item instanceof SimpleVariable simpleVariable) {
+                results.append(simpleVariable.toString());
             } else {
                 results.append(item);
             }
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/util/FunctionParser.java b/src/core/src/main/java/org/apache/jmeter/engine/util/FunctionParser.java
index d4a00763d6..9af0c9c7a5 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/util/FunctionParser.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/util/FunctionParser.java
@@ -72,7 +72,7 @@ class FunctionParser {
                     buffer.append(current[0]);
                 } else if (current[0] == '{' && previous == '$') {// found "${"
                     buffer.deleteCharAt(buffer.length() - 1);
-                    if (buffer.length() > 0) {// save leading text
+                    if (!buffer.isEmpty()) {// save leading text
                         result.add(buffer.toString());
                         buffer.setLength(0);
                     }
@@ -84,7 +84,7 @@ class FunctionParser {
                 }
             }
 
-            if (buffer.length() > 0) {
+            if (!buffer.isEmpty()) {
                 result.add(buffer.toString());
             }
         } catch (IOException e) {
@@ -127,8 +127,8 @@ class FunctionParser {
                 } else if (current[0] == '(' && previous != ' ') {
                     String funcName = buffer.toString();
                     function = CompoundVariable.getNamedFunction(funcName.trim());
-                    if (function instanceof Function) {
-                        ((Function) function).setParameters(parseParams(reader));
+                    if (function instanceof Function function1) {
+                        function1.setParameters(parseParams(reader));
                         if (firstNonSpace(reader, '#') != '}') {
                             reader.reset();// set to start of string
                             char []cb = new char[100];
@@ -136,8 +136,8 @@ class FunctionParser {
                             throw new InvalidVariableException("Expected } after "
                                     + funcName + " function call in " + new String(cb, 0, nbRead));
                         }
-                        if (function instanceof TestStateListener) {
-                            StandardJMeterEngine.register((TestStateListener) function);
+                        if (function instanceof TestStateListener testStateListener) {
+                            StandardJMeterEngine.register(testStateListener);
                         }
                         return function;
                     } else { // Function does not exist, so treat as per missing variable
@@ -145,8 +145,8 @@ class FunctionParser {
                     }
                 } else if (current[0] == '}') {// variable, or function with no parameter list
                     function = CompoundVariable.getNamedFunction(buffer.toString());
-                    if (function instanceof Function){// ensure that setParameters() is called.
-                        ((Function) function).setParameters(new ArrayList<>());
+                    if (function instanceof Function function1){// ensure that setParameters() is called.
+                        function1.setParameters(new ArrayList<>());
                     }
                     buffer.setLength(0);
                     return function;
@@ -211,7 +211,7 @@ class FunctionParser {
                     result.add(param);
                 } else if (current[0] == ')' && functionRecursion == 0 && parenRecursion == 0) {
                     // Detect functionName() so this does not generate empty string as the parameter
-                    if (buffer.length() == 0 && result.isEmpty()){
+                    if (buffer.isEmpty() && result.isEmpty()){
                         return result;
                     }
                     // Normal exit occurs here
diff --git a/src/core/src/main/java/org/apache/jmeter/engine/util/ValueReplacer.java b/src/core/src/main/java/org/apache/jmeter/engine/util/ValueReplacer.java
index 42d37651f7..5c9594effc 100644
--- a/src/core/src/main/java/org/apache/jmeter/engine/util/ValueReplacer.java
+++ b/src/core/src/main/java/org/apache/jmeter/engine/util/ValueReplacer.java
@@ -171,8 +171,7 @@ public class ValueReplacer {
             } else if (val instanceof NumberProperty) {
                 val = transform.transform(val);
                 log.debug("Replacement result: {}", val);
-            } else if (val instanceof MultiProperty) {
-                MultiProperty multiVal = (MultiProperty) val;
+            } else if (val instanceof MultiProperty multiVal) {
                 Collection<JMeterProperty> newValues = replaceValues(multiVal.iterator(), transform);
                 multiVal.clear();
                 for (JMeterProperty jmp : newValues) {
diff --git a/src/core/src/main/java/org/apache/jmeter/functions/gui/FunctionHelper.java b/src/core/src/main/java/org/apache/jmeter/functions/gui/FunctionHelper.java
index eca5090967..4e85d43f61 100644
--- a/src/core/src/main/java/org/apache/jmeter/functions/gui/FunctionHelper.java
+++ b/src/core/src/main/java/org/apache/jmeter/functions/gui/FunctionHelper.java
@@ -275,7 +275,7 @@ public class FunctionHelper extends JDialog implements ActionListener, ChangeLis
     static String buildFunctionCallString(String functionName, Arguments args) {
         StringBuilder functionCall = new StringBuilder("${");
         functionCall.append(functionName);
-        if (args.getArguments().size() > 0) {
+        if (!args.getArguments().isEmpty()) {
             functionCall.append("(");
             PropertyIterator iter = args.iterator();
             boolean first = true;
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/AbstractJMeterGuiComponent.java b/src/core/src/main/java/org/apache/jmeter/gui/AbstractJMeterGuiComponent.java
index ddafba9c21..d3f5615bc5 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/AbstractJMeterGuiComponent.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/AbstractJMeterGuiComponent.java
@@ -279,7 +279,7 @@ public abstract class AbstractJMeterGuiComponent extends JPanel implements JMete
         // JMeter removes disabled elements early from the tree, so configuration elements
         // with enabled=false (~HTTP Request Defaults) can't unexpectedly override the regular ones
         // like HTTP Request.
-        mc.set(TestElementSchema.INSTANCE.getEnabled(), enabled ? null : Boolean.FALSE);
+        mc.set(TestElementSchema.INSTANCE.getEnabled(), enabled ? null : false);
         // Note: we can't use editors for "comments" as getComments() is not a final method, so plugins might
         // override it and provide a different implementation.
         String comment = getComment();
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/GuiPackage.java b/src/core/src/main/java/org/apache/jmeter/gui/GuiPackage.java
index 231270e6f0..a08b0f5a9c 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/GuiPackage.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/GuiPackage.java
@@ -571,12 +571,10 @@ public final class GuiPackage implements LocaleChangeListener, HistoryListener {
      *
      * @return the JMeter tree model
      */
-    /*
-     * TODO consider removing this method, and providing method wrappers instead.
-     * This would allow the Gui package to do any additional clearups if required,
-     * as has been done with clearTestPlan()
-    */
     public JMeterTreeModel getTreeModel() {
+        // TODO consider removing this method, and providing method wrappers instead.
+        //   This would allow the Gui package to do any additional clearups if required,
+        //   as has been done with clearTestPlan()
         return treeModel;
     }
 
@@ -909,9 +907,9 @@ public final class GuiPackage implements LocaleChangeListener, HistoryListener {
         PropertyIterator it = el.propertyIterator();
         while (it.hasNext()) {
             JMeterProperty obj = it.next();
-            if (obj instanceof TestElementProperty) {
+            if (obj instanceof TestElementProperty jMeterProperties) {
                 ret ^= getTestElementCheckSum(
-                        ((TestElementProperty) obj).getElement());
+                        jMeterProperties.getElement());
             } else {
                 ret ^= obj.getName().hashCode();
                 String stringValue = obj.getStringValue();
@@ -985,8 +983,7 @@ public final class GuiPackage implements LocaleChangeListener, HistoryListener {
      * @return boolean
      */
     public boolean shouldSaveBeforeRunByPreference() {
-        return Boolean.TRUE.toString().
-                equalsIgnoreCase(PREFS.get(SBR_PREFS_KEY, null));
+        return "true".equalsIgnoreCase(PREFS.get(SBR_PREFS_KEY, null));
     }
 
     /**
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/HtmlReportUI.java b/src/core/src/main/java/org/apache/jmeter/gui/HtmlReportUI.java
index 0c55e5efee..5929e570a4 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/HtmlReportUI.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/HtmlReportUI.java
@@ -159,7 +159,7 @@ public class HtmlReportUI implements ActionListener {
     private class ReportGenerationWorker extends SwingWorker<List<String>, String> {
         private final JButton reportLaunchButton;
 
-        public ReportGenerationWorker(JButton reportLaunchButton) {
+        private ReportGenerationWorker(JButton reportLaunchButton) {
             this.reportLaunchButton = reportLaunchButton;
         }
         @Override
@@ -196,36 +196,32 @@ public class HtmlReportUI implements ActionListener {
     @Override
     public void actionPerformed(ActionEvent e) {
         switch (e.getActionCommand()) {
-        case CREATE_REQUEST:
-            try {
-                reportArea.setText(GENERATING_REPORT_LABEL + "\n");
-                reportLaunchButton.setIcon(runningIcon);
-                new ReportGenerationWorker(reportLaunchButton).execute();
-            } catch (Exception exception) {
-                if (LOGGER.isErrorEnabled()) {
-                    LOGGER.error("Error during html report generation: {}", exception.getMessage(), exception);
+            case CREATE_REQUEST -> {
+                try {
+                    reportArea.setText(GENERATING_REPORT_LABEL + "\n");
+                    reportLaunchButton.setIcon(runningIcon);
+                    new ReportGenerationWorker(reportLaunchButton).execute();
+                } catch (Exception exception) {
+                    if (LOGGER.isErrorEnabled()) {
+                        LOGGER.error("Error during html report generation: {}", exception.getMessage(), exception);
+                    }
+                }
+                if (LOGGER.isDebugEnabled()) {
+                    LOGGER.debug("CSV file path {}\nuser.properties file path: {}\nOutput directory file path: {}",
+                            csvFilePathTextField.getText(), userPropertiesFilePathTextField.getText(),
+                            outputDirectoryPathTextField.getText());
                 }
             }
-            if (LOGGER.isDebugEnabled()) {
-                LOGGER.debug("CSV file path {}\nuser.properties file path: {}\nOutput directory file path: {}",
-                        csvFilePathTextField.getText(), userPropertiesFilePathTextField.getText(),
-                        outputDirectoryPathTextField.getText());
-            }
-            break;
-        case BROWSE_USER_PROPERTIES:
-            userPropertiesFilePathTextField.setText(showFileChooser(userPropertiesFileButton.getParent(),
-                    userPropertiesFilePathTextField, false, new String[] { ".properties" }));
-            break;
-        case BROWSE_CSV:
-            csvFilePathTextField.setText(showFileChooser(csvFileButton.getParent(), csvFilePathTextField, false,
-                    new String[] { ".jtl", ".csv" }));
-            break;
-        case BROWSE_OUTPUT:
-            outputDirectoryPathTextField.setText(
+            case BROWSE_USER_PROPERTIES ->
+                    userPropertiesFilePathTextField.setText(showFileChooser(userPropertiesFileButton.getParent(),
+                            userPropertiesFilePathTextField, false, new String[]{".properties"}));
+            case BROWSE_CSV ->
+                    csvFilePathTextField.setText(showFileChooser(csvFileButton.getParent(), csvFilePathTextField, false,
+                            new String[]{".jtl", ".csv"}));
+            case BROWSE_OUTPUT -> outputDirectoryPathTextField.setText(
                     showFileChooser(outputDirectoryButton.getParent(), outputDirectoryPathTextField, true, null));
-            break;
-        default:
-            break;
+            default -> {
+            }
         }
     }
 
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/LoggerPanel.java b/src/core/src/main/java/org/apache/jmeter/gui/LoggerPanel.java
index 6e380a7f8c..d33b6c81d1 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/LoggerPanel.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/LoggerPanel.java
@@ -105,9 +105,6 @@ public class LoggerPanel extends JPanel implements GuiLogEventListener {
         return jTextArea;
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.gui.logging.GuiLogEventListener#processLogEvent(org.apache.jmeter.gui.logging.LogEventObject)
-     */
     @Override
     public void processLogEvent(final LogEventObject logEventObject) {
         if(!LOGGER_PANEL_RECEIVE_WHEN_CLOSED && !GuiPackage.getInstance().getMenuItemLoggerPanel().getModel().isSelected()) {
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/MainFrame.java b/src/core/src/main/java/org/apache/jmeter/gui/MainFrame.java
index bfc46e01f6..bab760e694 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/MainFrame.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/MainFrame.java
@@ -669,10 +669,10 @@ public class MainFrame extends JFrame implements TestStateListener, Remoteable,
                 TreePath path = this.getPathForLocation(event.getX(), event.getY());
                 if (path != null) {
                     Object treeNode = path.getLastPathComponent();
-                    if (treeNode instanceof DefaultMutableTreeNode) {
-                        Object testElement = ((DefaultMutableTreeNode) treeNode).getUserObject();
-                        if (testElement instanceof TestElement) {
-                            String comment = ((TestElement) testElement).getComment();
+                    if (treeNode instanceof DefaultMutableTreeNode defaultMutableTreeNode) {
+                        Object testElement = defaultMutableTreeNode.getUserObject();
+                        if (testElement instanceof TestElement element) {
+                            String comment = element.getComment();
                             if (StringUtilities.isNotBlank(comment)) {
                                 return comment.length() <= 80 ? comment : comment.substring(0, 77) + "...";
                             }
@@ -767,7 +767,7 @@ public class MainFrame extends JFrame implements TestStateListener, Remoteable,
             }
         }
 
-        /*
+        /**
          * Bug 62336: On Windows CTRL+6 doesn't give us an actionCommand, so
          * we have to try harder and read the KeyEvent from the EventQueue
          */
@@ -777,8 +777,7 @@ public class MainFrame extends JFrame implements TestStateListener, Remoteable,
                 return actionCommand;
             }
             AWTEvent currentEvent = EventQueue.getCurrentEvent();
-            if (currentEvent instanceof KeyEvent) {
-                KeyEvent keyEvent = (KeyEvent) currentEvent;
+            if (currentEvent instanceof KeyEvent keyEvent) {
                 return KeyEvent.getKeyText(keyEvent.getKeyCode());
             }
             log.debug("No keycode could be found for this actionEvent {}", actionEvent);
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/NamePanel.java b/src/core/src/main/java/org/apache/jmeter/gui/NamePanel.java
index d109c1c13e..2651765d73 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/NamePanel.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/NamePanel.java
@@ -80,15 +80,13 @@ public class NamePanel extends JPanel implements JMeterGUIComponent {
      */
     @Override
     public String getName() {
-        /*
-         * Null check is needed because some implementations of JPanel end up calling
-         * getName(). This is a bug, which has been reported as:
-         * http://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8175888
-         *
-         * See also
-         * https://www.securecoding.cert.org/confluence/display/java/MET05-J.+Ensure+that+constructors+do+not+call+overridable+methods
-         * https://dev.eclipse.org/sonar/coding_rules#rule_key=squid%3AS1699
-         */
+        // Null check is needed because some implementations of JPanel end up calling
+        // getName(). This is a bug, which has been reported as:
+        // http://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8175888
+        //
+        // See also
+        // https://www.securecoding.cert.org/confluence/display/java/MET05-J.+Ensure+that+constructors+do+not+call+overridable+methods
+        // https://dev.eclipse.org/sonar/coding_rules#rule_key=squid%3AS1699
         if (nameField != null) { // NOSONAR suppress warning as the null check is needed as per above
             return nameField.getText();
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/AbstractAction.java b/src/core/src/main/java/org/apache/jmeter/gui/action/AbstractAction.java
index 0519562497..898dc05456 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/AbstractAction.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/AbstractAction.java
@@ -92,16 +92,15 @@ public abstract class AbstractAction implements Command {
             File f = new File(rc.getFilename());
             if (f.exists()) {
                 switch (actionOnFile) {
-                    case APPEND:
-                        break;
-                    case DELETE:
-                        if (f.delete()) {
-                            break;
-                        } else {
+                    case APPEND -> {
+                    }
+                    case DELETE -> {
+                        if (!f.delete()) {
                             log.error("Could not delete existing file {}", f.getAbsolutePath());
                             return false;
                         }
-                    case ASK:
+                    }
+                    case ASK -> {
                         String[] option = new String[]{JMeterUtils.getResString("concat_result"),
                                 JMeterUtils.getResString("dont_start"), JMeterUtils.getResString("replace_file")};
                         String question = MessageFormat.format(
@@ -133,7 +132,7 @@ public abstract class AbstractAction implements Command {
                                 // Exit without start the test
                                 return false;
                         }
-                        break;
+                    }
                 }
             }
         }
@@ -147,15 +146,13 @@ public abstract class AbstractAction implements Command {
     protected static JFrame getParentFrame(ActionEvent event) {
         JFrame parent = null;
         Object source = event.getSource();
-        if (source instanceof JMenuItem) {
-            JMenuItem item = (JMenuItem) source;
+        if (source instanceof JMenuItem item) {
             Component comp = item.getParent();
-            if (comp instanceof JPopupMenu) {
-                JPopupMenu popup = (JPopupMenu) comp;
+            if (comp instanceof JPopupMenu popup) {
                 comp = popup.getInvoker();
-                Window window = SwingUtilities.windowForComponent((Component) comp);
-                if (window instanceof JFrame) {
-                    parent = (JFrame) window;
+                Window window = SwingUtilities.windowForComponent(comp);
+                if (window instanceof JFrame jFrame) {
+                    parent = jFrame;
                 }
             }
         } else {
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/Clear.java b/src/core/src/main/java/org/apache/jmeter/gui/action/Clear.java
index a3f3a3998b..053b06f8bd 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/Clear.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/Clear.java
@@ -61,15 +61,14 @@ public class Clear extends AbstractAction {
         final String actionCommand = e.getActionCommand();
         if (actionCommand.equals(ActionNames.CLEAR)) {
             JMeterGUIComponent guiComp = guiPackage.getCurrentGui();
-            if (guiComp instanceof Clearable){
-                ((Clearable) guiComp).clearData();
+            if (guiComp instanceof Clearable clearable){
+                clearable.clearData();
             }
         } else {
             guiPackage.getMainFrame().clearData();
             for (JMeterTreeNode node : guiPackage.getTreeModel().getNodesOfType(Clearable.class)) {
                 JMeterGUIComponent guiComp = guiPackage.getGui(node.getTestElement());
-                if (guiComp instanceof Clearable){
-                    Clearable item = (Clearable) guiComp;
+                if (guiComp instanceof Clearable item){
                     try {
                         item.clearData();
                     } catch (Exception ex) {
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/CompileJSR223TestElements.java b/src/core/src/main/java/org/apache/jmeter/gui/action/CompileJSR223TestElements.java
index 0c7b599542..d25400924b 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/CompileJSR223TestElements.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/CompileJSR223TestElements.java
@@ -58,7 +58,7 @@ public class CompileJSR223TestElements extends AbstractAction implements MenuCre
      */
     private static class JSR223TestElementCompilerVisitor implements HashTreeTraverser {
         private int elementsWithCompilationErrors = 0;
-        public JSR223TestElementCompilerVisitor() {
+        private JSR223TestElementCompilerVisitor() {
             super();
         }
         @Override
@@ -66,8 +66,7 @@ public class CompileJSR223TestElements extends AbstractAction implements MenuCre
             JMeterTreeNode treeNode = (JMeterTreeNode) object;
             Object userObject = treeNode.getUserObject();
             treeNode.setMarkedBySearch(false);
-            if (treeNode.isEnabled() && (userObject instanceof JSR223TestElement)) {
-                JSR223TestElement element = (JSR223TestElement) userObject;
+            if (treeNode.isEnabled() && (userObject instanceof JSR223TestElement element)) {
                 TestBeanHelper.prepare(element);
                 try {
                     log.info("Compiling JSR223 element named: '{}'", element.getName());
@@ -92,10 +91,11 @@ public class CompileJSR223TestElements extends AbstractAction implements MenuCre
         public void processPath() {
             // NOOP
         }
+
         /**
          * @return the elementsWithCompilationErrors
          */
-        public int getElementsWithCompilationErrors() {
+        private int getElementsWithCompilationErrors() {
             return elementsWithCompilationErrors;
         }
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/Copy.java b/src/core/src/main/java/org/apache/jmeter/gui/action/Copy.java
index 3979512efe..4e12219808 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/Copy.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/Copy.java
@@ -52,9 +52,6 @@ public class Copy extends AbstractAction {
         commands.add(ActionNames.COPY);
     }
 
-    /*
-     * @see org.apache.jmeter.gui.action.Command#getActionNames()
-     */
     @Override
     public Set<String> getActionNames() {
         return commands;
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/Duplicate.java b/src/core/src/main/java/org/apache/jmeter/gui/action/Duplicate.java
index 996cc149e8..b2ed8d7048 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/Duplicate.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/Duplicate.java
@@ -40,9 +40,6 @@ public class Duplicate extends AbstractAction {
         commands.add(ActionNames.DUPLICATE);
     }
 
-    /*
-     * @see org.apache.jmeter.gui.action.Command#getActionNames()
-     */
     @Override
     public Set<String> getActionNames() {
         return commands;
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/Help.java b/src/core/src/main/java/org/apache/jmeter/gui/action/Help.java
index 78f9767b5a..375b66aeba 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/Help.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/Help.java
@@ -77,15 +77,12 @@ public class Help extends AbstractAction {
             JDialog dialog = initHelpWindow();
             dialog.setVisible(true); // set the window visible immediately
 
-            /*
-             * This means that a new page will be shown before rendering is complete,
-             * however the correct location will be displayed.
-             * Attempts to use a "page" PropertyChangeListener to detect when the page
-             * has been loaded failed to work any better.
-             */
+            // This means that a new page will be shown before rendering is complete,
+            // however the correct location will be displayed.
+            // Attempts to use a "page" PropertyChangeListener to detect when the page
+            // has been loaded failed to work any better.
             StringBuilder url=new StringBuilder();
-            if (e.getSource() instanceof String[]) {
-                String[] source = (String[]) e.getSource();
+            if (e.getSource() instanceof String[] source) {
                 url.append(source[0]).append('#').append(source[1]);
             } else {
                 url.append(HELP_COMPONENTS).append('#').append(GuiPackage.getInstance().getTreeListener().getCurrentNode().getDocAnchor());
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/LoadRecentProject.java b/src/core/src/main/java/org/apache/jmeter/gui/action/LoadRecentProject.java
index a75554ca6a..127eb304cc 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/LoadRecentProject.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/LoadRecentProject.java
@@ -195,39 +195,18 @@ public class LoadRecentProject extends Load {
      * Get the KeyEvent to use as shortcut key for menu item
      */
     private static int getShortcutKey(int index) {
-        int shortKey = -1;
-        switch(index+1) {
-            case 1:
-                shortKey = KeyEvent.VK_1;
-                break;
-            case 2:
-                shortKey = KeyEvent.VK_2;
-                break;
-            case 3:
-                shortKey = KeyEvent.VK_3;
-                break;
-            case 4:
-                shortKey = KeyEvent.VK_4;
-                break;
-            case 5:
-                shortKey = KeyEvent.VK_5;
-                break;
-            case 6:
-                shortKey = KeyEvent.VK_6;
-                break;
-            case 7:
-                shortKey = KeyEvent.VK_7;
-                break;
-            case 8:
-                shortKey = KeyEvent.VK_8;
-                break;
-            case 9:
-                shortKey = KeyEvent.VK_9;
-                break;
-            default:
-                break;
-        }
-        return shortKey;
+        return switch (index + 1) {
+            case 1 -> KeyEvent.VK_1;
+            case 2 -> KeyEvent.VK_2;
+            case 3 -> KeyEvent.VK_3;
+            case 4 -> KeyEvent.VK_4;
+            case 5 -> KeyEvent.VK_5;
+            case 6 -> KeyEvent.VK_6;
+            case 7 -> KeyEvent.VK_7;
+            case 8 -> KeyEvent.VK_8;
+            case 9 -> KeyEvent.VK_9;
+            default -> -1;
+        };
     }
 
     /**
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/Save.java b/src/core/src/main/java/org/apache/jmeter/gui/action/Save.java
index 9572619b8f..f31e20198d 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/Save.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/Save.java
@@ -468,7 +468,7 @@ public class Save extends AbstractAction {
 
         private final Pattern pattern;
 
-        public PrivatePatternFileFilter(Pattern pattern) {
+        private PrivatePatternFileFilter(Pattern pattern) {
             if(pattern == null) {
                 throw new IllegalArgumentException("pattern cannot be null !"); //$NON-NLS-1$
             }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/SaveGraphics.java b/src/core/src/main/java/org/apache/jmeter/gui/action/SaveGraphics.java
index c73cabefc3..6fe65f06b1 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/SaveGraphics.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/SaveGraphics.java
@@ -81,8 +81,8 @@ public class SaveGraphics extends AbstractAction {
         if (e.getActionCommand().equals(ActionNames.SAVE_GRAPHICS)) {
             JMeterGUIComponent component = GuiPackage.getInstance().getCurrentGui();
             // get the JComponent from the visualizer
-            if (component instanceof Printable) {
-                JComponent comp = ((Printable) component).getPrintableComponent();
+            if (component instanceof Printable printable) {
+                JComponent comp = printable.getPrintableComponent();
                 saveImage(comp);
             }
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/SearchTreeDialog.java b/src/core/src/main/java/org/apache/jmeter/gui/action/SearchTreeDialog.java
index dc54b00243..5146a7e40b 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/SearchTreeDialog.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/SearchTreeDialog.java
@@ -471,8 +471,7 @@ public class SearchTreeDialog extends JDialog implements ActionListener { // NOS
     private static Map.Entry<Integer, JMeterTreeNode> doReplacementInCurrentNode(JMeterTreeNode jMeterTreeNode,
             String regex, String replaceBy, boolean caseSensitiveReplacement) {
         try {
-            if (jMeterTreeNode.getUserObject() instanceof Replaceable) {
-                Replaceable replaceable = (Replaceable) jMeterTreeNode.getUserObject();
+            if (jMeterTreeNode.getUserObject() instanceof Replaceable replaceable) {
                 int numberOfReplacements = replaceable.replace(regex, replaceBy, caseSensitiveReplacement);
                 if (numberOfReplacements > 0) {
                     if (logger.isInfoEnabled()) {
@@ -488,9 +487,6 @@ public class SearchTreeDialog extends JDialog implements ActionListener { // NOS
         return null;
     }
 
-    /* (non-Javadoc)
-     * @see java.awt.Dialog#setVisible(boolean)
-     */
     @Override
     public void setVisible(boolean b) {
         super.setVisible(b);
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/Start.java b/src/core/src/main/java/org/apache/jmeter/gui/action/Start.java
index b31d1f3d73..3c2771d635 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/Start.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/Start.java
@@ -279,18 +279,11 @@ public class Start extends AbstractAction {
      * @return {@link TreeCloner}
      */
     private static ListedHashTree cloneTree(HashTree testTree, RunMode runMode) {
-        TreeCloner cloner = null;
-        switch (runMode) {
-            case VALIDATION:
-                cloner = createTreeClonerForValidation(false);
-                break;
-            case IGNORING_TIMERS:
-                cloner = new TreeClonerNoTimer(false);
-                break;
-            case AS_IS:
-                cloner = new TreeCloner(false);
-                break;
-        }
+        TreeCloner cloner = switch (runMode) {
+            case VALIDATION -> createTreeClonerForValidation(false);
+            case IGNORING_TIMERS -> new TreeClonerNoTimer(false);
+            case AS_IS -> new TreeCloner(false);
+        };
         testTree.traverse(cloner);
         return cloner.getClonedTree();
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/StopStoppables.java b/src/core/src/main/java/org/apache/jmeter/gui/action/StopStoppables.java
index f4f5ff60a6..007482f28b 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/StopStoppables.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/StopStoppables.java
@@ -47,25 +47,16 @@ public class StopStoppables extends AbstractAction implements ActionListener {
         super();
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.gui.action.AbstractAction#getActionNames()
-     */
     @Override
     public Set<String> getActionNames() {
         return commands;
     }
 
-    /* (non-Javadoc)
-     * @see java.awt.event.ActionListener#actionPerformed(java.awt.event.ActionEvent)
-     */
     @Override
     public void actionPerformed(ActionEvent e) {
 
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.gui.action.AbstractAction#doAction(java.awt.event.ActionEvent)
-     */
     @Override
     public void doAction(ActionEvent e) {
         GuiPackage instance = GuiPackage.getInstance();
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/action/validation/TreeClonerForValidation.java b/src/core/src/main/java/org/apache/jmeter/gui/action/validation/TreeClonerForValidation.java
index e2c797a7d9..8863b97ff6 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/action/validation/TreeClonerForValidation.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/action/validation/TreeClonerForValidation.java
@@ -79,16 +79,14 @@ public class TreeClonerForValidation extends TreeCloner {
             return node; // don't add timer or backend
         } else {
             Object clonedNode = super.addNodeToTree(node);
-            if(clonedNode instanceof org.apache.jmeter.threads.ThreadGroup) {
-                ThreadGroup tg = (ThreadGroup)clonedNode;
+            if(clonedNode instanceof ThreadGroup tg) {
                 tg.setNumThreads(VALIDATION_NUMBER_OF_THREADS);
                 tg.setScheduler(false);
                 tg.setProperty(ThreadGroup.DELAY, 0);
                 if(((AbstractThreadGroup)clonedNode).getSamplerController() instanceof LoopController) {
                     ((LoopController)((AbstractThreadGroup)clonedNode).getSamplerController()).setLoops(VALIDATION_ITERATIONS);
                 }
-            } else if (clonedNode instanceof OpenModelThreadGroup) {
-                OpenModelThreadGroup tg = (OpenModelThreadGroup) clonedNode;
+            } else if (clonedNode instanceof OpenModelThreadGroup tg) {
                 tg.setRandomSeedString("0");
                 // Launch all the iterations during the first second, and leave one hour for the threads to complete
                 tg.setScheduleString("rate(" + VALIDATION_ITERATIONS + " / sec) even_arrivals(1 sec) pause(1 hour)");
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/logging/LogEventObject.java b/src/core/src/main/java/org/apache/jmeter/gui/logging/LogEventObject.java
index 65c86be289..248ccc6bd5 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/logging/LogEventObject.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/logging/LogEventObject.java
@@ -39,8 +39,8 @@ public class LogEventObject extends EventObject {
 
     public LogEventObject(Object source, String seralizedString) {
         super(source);
-        if (source instanceof LogEvent) {
-            level = ((LogEvent) source).getLevel();
+        if (source instanceof LogEvent logEvent) {
+            level = logEvent.getLevel();
         }
         this.seralizedString = seralizedString;
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/menu/StaticJMeterGUIComponent.java b/src/core/src/main/java/org/apache/jmeter/gui/menu/StaticJMeterGUIComponent.java
index 7c39b898ed..0f086fc0f6 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/menu/StaticJMeterGUIComponent.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/menu/StaticJMeterGUIComponent.java
@@ -77,7 +77,7 @@ public class StaticJMeterGUIComponent implements JMeterGUIComponent {
 
     private static List<String> getGroups(Class<?> c, TestElementMetadata metadata) {
         String[] groups = metadata.actionGroups();
-        if (groups.length == 1 && groups[0].equals("")) {
+        if (groups.length == 1 && groups[0].isEmpty()) {
             // Annotations can't hold null values, so we use empty string instead
             return null;
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeModel.java b/src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeModel.java
index c9ec94b808..a2411135e7 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeModel.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeModel.java
@@ -112,8 +112,7 @@ public class JMeterTreeModel extends DefaultTreeModel {
     public HashTree addSubTree(HashTree subTree, JMeterTreeNode current) throws IllegalUserActionException {
         for (Object o : subTree.list()) {
             TestElement item = (TestElement) o;
-            if (item instanceof TestPlan) {
-                TestPlan tp = (TestPlan) item;
+            if (item instanceof TestPlan tp) {
                 current = (JMeterTreeNode) ((JMeterTreeNode) getRoot()).getChildAt(0);
                 final TestPlan userObject = (TestPlan) current.getUserObject();
                 userObject.addTestElement(item);
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeTransferHandler.java b/src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeTransferHandler.java
index 31e6fcd896..1d043b915b 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeTransferHandler.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeTransferHandler.java
@@ -280,7 +280,7 @@ public class JMeterTreeTransferHandler extends TransferHandler {
     private class NodesTransferable implements Transferable {
         private final JMeterTreeNode[] nodes;
 
-        public NodesTransferable(JMeterTreeNode[] nodes) {
+        private NodesTransferable(JMeterTreeNode[] nodes) {
             this.nodes = nodes;
         }
 
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/FileDialoger.java b/src/core/src/main/java/org/apache/jmeter/gui/util/FileDialoger.java
index 41b8f7b006..e2bdb87351 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/FileDialoger.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/FileDialoger.java
@@ -253,7 +253,7 @@ public final class FileDialoger {
     public static JFileChooser promptToSaveFile(String filename, String[] extensions) {
         if (lastJFCDirectory == null) {
             String start = System.getProperty("user.dir", "");//$NON-NLS-1$//$NON-NLS-2$
-            if (start.length() > 0) {
+            if (!start.isEmpty()) {
                 jfc = new JFileChooser(new File(start));
             }
             lastJFCDirectory = jfc.getCurrentDirectory().getAbsolutePath();
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/HeaderAsPropertyRendererWrapper.java b/src/core/src/main/java/org/apache/jmeter/gui/util/HeaderAsPropertyRendererWrapper.java
index 2678c8bdec..7cf658a988 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/HeaderAsPropertyRendererWrapper.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/HeaderAsPropertyRendererWrapper.java
@@ -52,8 +52,7 @@ public class HeaderAsPropertyRendererWrapper implements TableCellRenderer {
     @Override
     public Component getTableCellRendererComponent(JTable table, Object value,
             boolean isSelected, boolean hasFocus, int row, int column) {
-        if(delegate instanceof DefaultTableCellRenderer) {
-            DefaultTableCellRenderer tr = (DefaultTableCellRenderer) delegate;
+        if(delegate instanceof DefaultTableCellRenderer tr) {
             if (table != null) {
                 JTableHeader header = table.getTableHeader();
                 if (header != null){
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/HorizontalPanel.java b/src/core/src/main/java/org/apache/jmeter/gui/util/HorizontalPanel.java
index 145c31e7a2..2393c9982f 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/HorizontalPanel.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/HorizontalPanel.java
@@ -62,8 +62,8 @@ public class HorizontalPanel extends JPanel {
             subPanel.add(Box.createHorizontalStrut(hgap));
         }
 
-        if (c instanceof JComponent) {
-            ((JComponent) c).setAlignmentY(verticalAlign);
+        if (c instanceof JComponent jComponent) {
+            jComponent.setAlignmentY(verticalAlign);
         }
         return subPanel.add(c);
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/JDateField.java b/src/core/src/main/java/org/apache/jmeter/gui/util/JDateField.java
index 27b15538ea..b00de83db1 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/JDateField.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/JDateField.java
@@ -46,7 +46,7 @@ public class JDateField extends JTextField {
     // Datefields are not thread-safe
     private final DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss"); // $NON-NLS-1$
 
-    /*
+    /**
      * The following array must agree with dateFormat
      *
      * It is used to translate the positions in the buffer to the values used by
@@ -122,7 +122,7 @@ public class JDateField extends JTextField {
         }
     }
 
-    /*
+    /**
      * Convert position in buffer to Calendar type Assumes that pos >=0 (which
      * is true for getCaretPosition())
      */
@@ -147,7 +147,7 @@ public class JDateField extends JTextField {
         return c;
     }
 
-    /*
+    /**
      * Update the current field. The addend is only expected to be +1/-1, but
      * other values will work. N.B. the roll() method only supports changes by a
      * single unit - up or down
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/JMeterMenuBar.java b/src/core/src/main/java/org/apache/jmeter/gui/util/JMeterMenuBar.java
index 4f829e9d2e..b5fed49b82 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/JMeterMenuBar.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/JMeterMenuBar.java
@@ -395,12 +395,10 @@ public class JMeterMenuBar extends JMenuBar implements LocaleChangeListener {
 
         LangMenuHelper langMenu = new LangMenuHelper(languageMenu);
 
-        /*
-         * Note: the item name is used by ChangeLanguage to create a Locale for
-         * that language, so need to ensure that the language strings are valid
-         * If they exist, use the Locale language constants.
-         * Also, need to ensure that the names are valid resource entries too.
-         */
+        // Note: the item name is used by ChangeLanguage to create a Locale for
+        // that language, so need to ensure that the language strings are valid
+        // If they exist, use the Locale language constants.
+        // Also, need to ensure that the names are valid resource entries too.
 
         Locale currentLocale = JMeterUtils.getLocale();
         String selectedLocale = currentLocale == null ? "" : currentLocale.toString();
@@ -705,8 +703,7 @@ public class JMeterMenuBar extends JMenuBar implements LocaleChangeListener {
                     return;
                 }
             }
-            if (component instanceof JMenu) {
-                final JMenu jMenu = (JMenu) component;
+            if (component instanceof JMenu jMenu) {
                 if (isResource(jMenu.getActionCommand())){
                     jMenu.setText(JMeterUtils.getResString(compName));
                 }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/JMeterToolBar.java b/src/core/src/main/java/org/apache/jmeter/gui/util/JMeterToolBar.java
index 801f626ab1..759edae5af 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/JMeterToolBar.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/JMeterToolBar.java
@@ -95,9 +95,8 @@ public class JMeterToolBar extends JToolBar implements LocaleChangeListener {
     @Override
     protected void addImpl(Component comp, Object constraints, int index) {
         super.addImpl(comp, constraints, index);
-        if (comp instanceof JButton) {
+        if (comp instanceof JButton b) {
             // Ensure buttons added to the toolbar have the same style.
-            JButton b = (JButton) comp;
             b.setFocusable(false);
             if (b.isBorderPainted() && (b.getText() == null || b.getText().isEmpty())) {
                 b.setRolloverEnabled(true);
@@ -245,8 +244,7 @@ public class JMeterToolBar extends JToolBar implements LocaleChangeListener {
         Component[] components = getComponents();
         Map<String, Boolean> buttonStates = new HashMap<>(components.length);
         for (Component component : components) {
-            if (component instanceof JButton) {
-                JButton button = (JButton) component;
+            if (component instanceof JButton button) {
                 buttonStates.put(button.getActionCommand(), button.isEnabled());
             }
         }
@@ -258,15 +256,15 @@ public class JMeterToolBar extends JToolBar implements LocaleChangeListener {
      */
     public void initButtonsState() {
         Map<String, Boolean> buttonStates = new HashMap<>();
-        buttonStates.put(ActionNames.ACTION_START, Boolean.TRUE);
-        buttonStates.put(ActionNames.ACTION_START_NO_TIMERS, Boolean.TRUE);
-        buttonStates.put(ActionNames.ACTION_STOP, Boolean.FALSE);
-        buttonStates.put(ActionNames.ACTION_SHUTDOWN, Boolean.FALSE);
-        buttonStates.put(ActionNames.UNDO, Boolean.FALSE);
-        buttonStates.put(ActionNames.REDO, Boolean.FALSE);
-        buttonStates.put(ActionNames.REMOTE_START_ALL, Boolean.TRUE);
-        buttonStates.put(ActionNames.REMOTE_STOP_ALL, Boolean.FALSE);
-        buttonStates.put(ActionNames.REMOTE_SHUT_ALL, Boolean.FALSE);
+        buttonStates.put(ActionNames.ACTION_START, true);
+        buttonStates.put(ActionNames.ACTION_START_NO_TIMERS, true);
+        buttonStates.put(ActionNames.ACTION_STOP, false);
+        buttonStates.put(ActionNames.ACTION_SHUTDOWN, false);
+        buttonStates.put(ActionNames.UNDO, false);
+        buttonStates.put(ActionNames.REDO, false);
+        buttonStates.put(ActionNames.REMOTE_START_ALL, true);
+        buttonStates.put(ActionNames.REMOTE_STOP_ALL, false);
+        buttonStates.put(ActionNames.REMOTE_SHUT_ALL, false);
         updateButtons(buttonStates);
     }
 
@@ -327,8 +325,7 @@ public class JMeterToolBar extends JToolBar implements LocaleChangeListener {
         boolean synchronous = false;
         JMeterUtils.runSafe(synchronous, () -> {
             for (Component component : getComponents()) {
-                if (component instanceof JButton) {
-                    JButton button = (JButton) component;
+                if (component instanceof JButton button) {
                     Boolean enabled = buttonStates.get(button.getActionCommand());
                     if (enabled != null) {
                         button.setEnabled(enabled);
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/NumberFieldErrorListener.java b/src/core/src/main/java/org/apache/jmeter/gui/util/NumberFieldErrorListener.java
index 847af66d24..f882b2f337 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/NumberFieldErrorListener.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/NumberFieldErrorListener.java
@@ -39,10 +39,10 @@ public class NumberFieldErrorListener extends FocusAdapter {
     public void focusLost(FocusEvent e) {
         Component source = (Component) e.getSource();
         String text = "";
-        if (source instanceof JTextComponent) {
-            text = ((JTextComponent) source).getText();
-        } else if (source instanceof TextComponent) {
-            text = ((TextComponent) source).getText();
+        if (source instanceof JTextComponent jTextComponent) {
+            text = jTextComponent.getText();
+        } else if (source instanceof TextComponent textComponent) {
+            text = textComponent.getText();
         }
         try {
             Integer.parseInt(text);
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/PowerTableModel.java b/src/core/src/main/java/org/apache/jmeter/gui/util/PowerTableModel.java
index b51d0a4768..c5bd87013d 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/PowerTableModel.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/PowerTableModel.java
@@ -40,7 +40,7 @@ public class PowerTableModel extends DefaultTableModel {
     private Class<?>[] columnClasses;
 
     private static final List<Object> DEFAULT_ARGS = Collections.unmodifiableList(Arrays.asList("", 0,
-            0L, Boolean.FALSE, 0F, 0D, ' ',
+            0L, false, 0F, 0D, ' ',
             Byte.MIN_VALUE, Short.MIN_VALUE));
 
     public PowerTableModel(String[] headers, Class<?>[] classes) {
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/TextAreaTableCellEditor.java b/src/core/src/main/java/org/apache/jmeter/gui/util/TextAreaTableCellEditor.java
index e4d3fdb07c..b8058d2a8e 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/TextAreaTableCellEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/TextAreaTableCellEditor.java
@@ -246,8 +246,8 @@ public class TextAreaTableCellEditor extends AbstractCellEditor implements Table
          * @see #shouldSelectCell
          */
         public boolean isCellEditable(EventObject anEvent) {
-            if (anEvent instanceof MouseEvent) {
-                return ((MouseEvent) anEvent).getClickCount() >= clickCountToStart;
+            if (anEvent instanceof MouseEvent mouseEvent) {
+                return mouseEvent.getClickCount() >= clickCountToStart;
             }
             return true;
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/TristateCheckBox.java b/src/core/src/main/java/org/apache/jmeter/gui/util/TristateCheckBox.java
index 1698c9a062..5153ee63c5 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/TristateCheckBox.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/TristateCheckBox.java
@@ -181,10 +181,10 @@ public final class TristateCheckBox extends JCheckBox {
         // Fire ActionEvent
         int modifiers = 0;
         AWTEvent currentEvent = EventQueue.getCurrentEvent();
-        if (currentEvent instanceof InputEvent) {
-            modifiers = ((InputEvent) currentEvent).getModifiers();
-        } else if (currentEvent instanceof ActionEvent) {
-            modifiers = ((ActionEvent) currentEvent).getModifiers();
+        if (currentEvent instanceof InputEvent inputEvent) {
+            modifiers = inputEvent.getModifiers();
+        } else if (currentEvent instanceof ActionEvent actionEvent) {
+            modifiers = actionEvent.getModifiers();
         }
         fireActionPerformed(new ActionEvent(this,
                 ActionEvent.ACTION_PERFORMED, getText(),
@@ -204,7 +204,7 @@ public final class TristateCheckBox extends JCheckBox {
         private final Icon icon;
         private final boolean original;
 
-        public TristateButtonModel(TristateState initial,
+        private TristateButtonModel(TristateState initial,
                 TristateCheckBox tristateCheckBox, boolean original) {
             setState(initial);
             this.tristateCheckBox = tristateCheckBox;
@@ -212,11 +212,11 @@ public final class TristateCheckBox extends JCheckBox {
             this.original = original;
         }
 
-        public void setIndeterminate() {
+        private void setIndeterminate() {
             setState(TristateState.INDETERMINATE);
         }
 
-        public boolean isIndeterminate() {
+        private boolean isIndeterminate() {
             return state == TristateState.INDETERMINATE;
         }
 
@@ -286,7 +286,7 @@ public final class TristateCheckBox extends JCheckBox {
 
         }
 
-        public TristateState getState() {
+        private TristateState getState() {
             return state;
         }
     }
@@ -301,7 +301,7 @@ public final class TristateCheckBox extends JCheckBox {
         private final int iconHeight;
         private final int iconWidth;
 
-        public TristateCheckBoxIcon() {
+        private TristateCheckBoxIcon() {
             // Assume that the UI has not changed since the checkbox was created
             UIDefaults defaults = UIManager.getLookAndFeelDefaults();
             Icon icon = defaults.getIcon("CheckBox.icon");
diff --git a/src/core/src/main/java/org/apache/jmeter/gui/util/VerticalPanel.java b/src/core/src/main/java/org/apache/jmeter/gui/util/VerticalPanel.java
index 4d72f72ace..4da731df6a 100644
--- a/src/core/src/main/java/org/apache/jmeter/gui/util/VerticalPanel.java
+++ b/src/core/src/main/java/org/apache/jmeter/gui/util/VerticalPanel.java
@@ -62,8 +62,8 @@ public class VerticalPanel extends JPanel {
             subPanel.add(Box.createVerticalStrut(vgap));
         }
 
-        if (c instanceof JComponent) {
-            ((JComponent) c).setAlignmentX(horizontalAlign);
+        if (c instanceof JComponent jComponent) {
+            jComponent.setAlignmentX(horizontalAlign);
         }
 
         return subPanel.add(c);
diff --git a/src/core/src/main/java/org/apache/jmeter/report/config/ReportGeneratorConfiguration.java b/src/core/src/main/java/org/apache/jmeter/report/config/ReportGeneratorConfiguration.java
index c7922aff9f..a26da10710 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/config/ReportGeneratorConfiguration.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/config/ReportGeneratorConfiguration.java
@@ -99,7 +99,7 @@ public class ReportGeneratorConfiguration {
     // Required graph properties
     // Exclude controllers
     public static final String GRAPH_KEY_EXCLUDE_CONTROLLERS = "exclude_controllers";
-    public static final Boolean GRAPH_KEY_EXCLUDE_CONTROLLERS_DEFAULT = Boolean.FALSE;
+    public static final Boolean GRAPH_KEY_EXCLUDE_CONTROLLERS_DEFAULT = false;
 
     // Title
     public static final String GRAPH_KEY_TITLE = "title";
@@ -108,7 +108,7 @@ public class ReportGeneratorConfiguration {
     // Required exporter properties
     // Filters only sample series ?
     public static final String EXPORTER_KEY_FILTERS_ONLY_SAMPLE_SERIES = "filters_only_sample_series";
-    public static final Boolean EXPORTER_KEY_FILTERS_ONLY_SAMPLE_SERIES_DEFAULT = Boolean.TRUE;
+    public static final Boolean EXPORTER_KEY_FILTERS_ONLY_SAMPLE_SERIES_DEFAULT = true;
 
     // Series filter
     public static final String EXPORTER_KEY_SERIES_FILTER = "series_filter";
@@ -116,7 +116,7 @@ public class ReportGeneratorConfiguration {
 
     // Show controllers only
     public static final String EXPORTER_KEY_SHOW_CONTROLLERS_ONLY = "show_controllers_only";
-    public static final Boolean EXPORTER_KEY_SHOW_CONTROLLERS_ONLY_DEFAULT = Boolean.FALSE;
+    public static final Boolean EXPORTER_KEY_SHOW_CONTROLLERS_ONLY_DEFAULT = false;
 
     // Optional exporter properties
     public static final String EXPORTER_KEY_GRAPH_EXTRA_OPTIONS = "graph_options";
@@ -645,7 +645,7 @@ public class ReportGeneratorConfiguration {
         final boolean ignoreTCFromTop5ErrorsBySampler = getRequiredProperty(
                 props,
                 REPORT_GENERATOR_KEY_EXCLUDE_TC_FROM_TOP5_ERRORS_BY_SAMPLER,
-                Boolean.TRUE,
+                true,
                 Boolean.class);
         configuration.setIgnoreTCFromTop5ErrorsBySampler(ignoreTCFromTop5ErrorsBySampler);
 
diff --git a/src/core/src/main/java/org/apache/jmeter/report/core/ControllerSamplePredicate.java b/src/core/src/main/java/org/apache/jmeter/report/core/ControllerSamplePredicate.java
index 0d97eed5cc..261084bcd5 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/core/ControllerSamplePredicate.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/core/ControllerSamplePredicate.java
@@ -24,13 +24,6 @@ package org.apache.jmeter.report.core;
  * @since 3.0
  */
 public class ControllerSamplePredicate implements SamplePredicate {
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SamplePredicate#matches(org.apache
-     * .jmeter.report.csv.core.Sample)
-     */
     @Override
     public boolean matches(Sample sample) {
         return sample.isController();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/core/Sample.java b/src/core/src/main/java/org/apache/jmeter/report/core/Sample.java
index efa09ff311..eeb0e13745 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/core/Sample.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/core/Sample.java
@@ -131,11 +131,6 @@ public class Sample {
         return getData(clazz, metadata.ensureIndexOf(name), name);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see java.lang.Object#toString()
-     */
     @Override
     public String toString() {
         return String.join(String.valueOf(metadata.getSeparator()), data);
diff --git a/src/core/src/main/java/org/apache/jmeter/report/core/SampleMetadata.java b/src/core/src/main/java/org/apache/jmeter/report/core/SampleMetadata.java
index 2728cb1e8e..9c689c5807 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/core/SampleMetadata.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/core/SampleMetadata.java
@@ -218,11 +218,6 @@ public class SampleMetadata {
         return index;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see java.lang.Object#toString()
-     */
     @Override
     public String toString() {
         return String.join(String.valueOf(separator), columns);
diff --git a/src/core/src/main/java/org/apache/jmeter/report/dashboard/AbstractDataExporter.java b/src/core/src/main/java/org/apache/jmeter/report/dashboard/AbstractDataExporter.java
index f52bf191d6..c141165e91 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/dashboard/AbstractDataExporter.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/dashboard/AbstractDataExporter.java
@@ -51,8 +51,7 @@ public abstract class AbstractDataExporter implements DataExporter {
     protected static <T> T findValue(Class<T> clazz, String data, ResultData root) {
         T value = null;
         ResultData result = findData(data, root);
-        if (result instanceof ValueResultData) {
-            ValueResultData valueResult = (ValueResultData) result;
+        if (result instanceof ValueResultData valueResult) {
             Object object = valueResult.getValue();
             if (object != null && clazz.isAssignableFrom(object.getClass())) {
                 value = clazz.cast(object);
@@ -73,21 +72,20 @@ public abstract class AbstractDataExporter implements DataExporter {
      */
     protected static ResultData findData(String data, ResultData root) {
         String[] pathItems = data.split("\\.");
-        if (pathItems == null || !(root instanceof MapResultData)) {
+        if (pathItems == null || !(root instanceof MapResultData map)) {
             return null;
         }
 
         ResultData result = null;
         int count = pathItems.length;
         int index = 0;
-        MapResultData map = (MapResultData) root;
         while (index < count && result == null) {
             ResultData current = map.getResult(pathItems[index]);
             if (index == count - 1) {
                 result = current;
             } else {
-                if (current instanceof MapResultData) {
-                    map = (MapResultData) current;
+                if (current instanceof MapResultData mapResultData) {
+                    map = mapResultData;
                     index++;
                 }
             }
@@ -95,22 +93,11 @@ public abstract class AbstractDataExporter implements DataExporter {
         return result;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.dashboard.DataExporter#getName()
-     */
     @Override
     public String getName() {
         return name;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.dashboard.DataExporter#setName(java.lang.String)
-     */
     @Override
     public void setName(String name) {
         this.name = name;
diff --git a/src/core/src/main/java/org/apache/jmeter/report/dashboard/HtmlTemplateExporter.java b/src/core/src/main/java/org/apache/jmeter/report/dashboard/HtmlTemplateExporter.java
index d36cc6a33f..9e65efa8d8 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/dashboard/HtmlTemplateExporter.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/dashboard/HtmlTemplateExporter.java
@@ -94,8 +94,8 @@ public class HtmlTemplateExporter extends AbstractDataExporter {
      * @param context {@link DataContext}
      */
     private static void addToContext(String key, Object value, DataContext context) {
-        if (value instanceof String) {
-            value = '"' + (String) value + '"';
+        if (value instanceof String s) {
+            value = '"' + s + '"';
         }
         context.put(key, value);
     }
@@ -118,17 +118,10 @@ public class HtmlTemplateExporter extends AbstractDataExporter {
          *
          * @param extraOptions to inject
          */
-        public final void setExtraOptions(SubConfiguration extraOptions) {
+        private void setExtraOptions(SubConfiguration extraOptions) {
             this.extraOptions = extraOptions;
         }
 
-        /*
-         * (non-Javadoc)
-         *
-         * @see org.apache.jmeter.report.dashboard.HtmlTemplateExporter.
-         * ResultCustomizer#customizeResult(org.apache.jmeter.report.processor.
-         * ResultData)
-         */
         @Override
         public ResultData customizeResult(ResultData result) {
             MapResultData customizedResult = new MapResultData();
@@ -162,11 +155,11 @@ public class HtmlTemplateExporter extends AbstractDataExporter {
         private boolean excludesControllers;
         private String graphId;
 
-        public final void setExcludesControllers(boolean excludesControllers) {
+        private void setExcludesControllers(boolean excludesControllers) {
             this.excludesControllers = excludesControllers;
         }
 
-        public final void setGraphId(String graphId) {
+        private void setGraphId(String graphId) {
             this.graphId = graphId;
         }
 
@@ -177,7 +170,7 @@ public class HtmlTemplateExporter extends AbstractDataExporter {
          * @param showControllerSeriesOnly flag to control visibility of controller
          * @param filterPattern to use
          */
-        public EmptyGraphChecker(boolean filtersOnlySampleSeries,
+        private EmptyGraphChecker(boolean filtersOnlySampleSeries,
                 boolean showControllerSeriesOnly, Pattern filterPattern) {
             this.filtersOnlySampleSeries = filtersOnlySampleSeries;
             this.showControllerSeriesOnly = showControllerSeriesOnly;
@@ -208,19 +201,17 @@ public class HtmlTemplateExporter extends AbstractDataExporter {
 
             // Detect whether none series matches the series filter.
             ResultData seriesResult = findData(AbstractGraphConsumer.RESULT_SERIES, result);
-            if (!(seriesResult instanceof ListResultData)) {
+            if (!(seriesResult instanceof ListResultData seriesList)) {
                 return true;
             }
 
             // Try to find at least one pattern matching
-            ListResultData seriesList = (ListResultData) seriesResult;
             int count = seriesList.getSize();
             int index = 0;
             boolean matches = false;
             while (index < count && !matches) {
                 ResultData currentResult = seriesList.get(index);
-                if (currentResult instanceof MapResultData) {
-                    MapResultData seriesData = (MapResultData) currentResult;
+                if (currentResult instanceof MapResultData seriesData) {
                     String name = findValue(String.class,
                             AbstractGraphConsumer.RESULT_SERIES_NAME,
                             seriesData);
@@ -470,8 +461,7 @@ public class HtmlTemplateExporter extends AbstractDataExporter {
             String resultKey, Map<String, Object> storage, DataContext dataContext,
             ResultDataVisitor<T> visitor, ResultCustomizer customizer, ResultChecker checker) {
         Object data = storage.get(resultKey);
-        if (data instanceof ResultData) {
-            ResultData result = (ResultData) data;
+        if (data instanceof ResultData result) {
             if (checker != null) {
                 checker.checkResult(dataContext, result);
             }
diff --git a/src/core/src/main/java/org/apache/jmeter/report/dashboard/JsonExporter.java b/src/core/src/main/java/org/apache/jmeter/report/dashboard/JsonExporter.java
index 2b05ed2610..81eb1cf6d6 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/dashboard/JsonExporter.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/dashboard/JsonExporter.java
@@ -68,9 +68,8 @@ public class JsonExporter extends AbstractDataExporter {
     public void export(SampleContext context, File file, ReportGeneratorConfiguration reportGeneratorConfiguration)
             throws ExportException {
         Object data = context.getData().get(ReportGenerator.STATISTICS_SUMMARY_CONSUMER_NAME);
-        if (data instanceof MapResultData) {
+        if (data instanceof MapResultData result) {
             LOGGER.info("Found data for consumer {} in context", ReportGenerator.STATISTICS_SUMMARY_CONSUMER_NAME);
-            MapResultData result = (MapResultData) data;
             Map<String, SamplingStatistic> statistics = new HashMap<>();
             MapResultData overallData = (MapResultData) result.getResult("overall");
             LOGGER.info("Creating statistics for overall");
diff --git a/src/core/src/main/java/org/apache/jmeter/report/dashboard/JsonizerVisitor.java b/src/core/src/main/java/org/apache/jmeter/report/dashboard/JsonizerVisitor.java
index 89b723c4f2..c469c97fa3 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/dashboard/JsonizerVisitor.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/dashboard/JsonizerVisitor.java
@@ -42,13 +42,6 @@ public class JsonizerVisitor implements ResultDataVisitor<String> {
     public JsonizerVisitor() {
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.ResultDataVisitor#visitListResult(
-     * org.apache.jmeter.report.processor.ListResultData)
-     */
     @Override
     public String visitListResult(ListResultData listResult) {
         String result = "";
@@ -63,13 +56,6 @@ public class JsonizerVisitor implements ResultDataVisitor<String> {
         return result;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.ResultDataVisitor#visitMapResult(org
-     * .apache.jmeter.report.processor.MapResultData)
-     */
     @Override
     public String visitMapResult(MapResultData mapResult) {
         String result = "";
@@ -83,13 +69,6 @@ public class JsonizerVisitor implements ResultDataVisitor<String> {
         return result;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.ResultDataVisitor#visitValueResult
-     * (org.apache.jmeter.report.processor.ValueResultData)
-     */
     @Override
     public String visitValueResult(ValueResultData valueResult) {
         String result = "";
diff --git a/src/core/src/main/java/org/apache/jmeter/report/dashboard/TemplateVisitor.java b/src/core/src/main/java/org/apache/jmeter/report/dashboard/TemplateVisitor.java
index 1e8fa7a966..55bfb3d01e 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/dashboard/TemplateVisitor.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/dashboard/TemplateVisitor.java
@@ -75,12 +75,6 @@ public class TemplateVisitor extends SimpleFileVisitor<Path> {
         this.data = data;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see java.nio.file.SimpleFileVisitor#preVisitDirectory(java.lang.Object,
-     * java.nio.file.attribute.BasicFileAttributes)
-     */
     @Override
     public FileVisitResult preVisitDirectory(Path file, BasicFileAttributes attrs)
             throws IOException {
@@ -99,12 +93,6 @@ public class TemplateVisitor extends SimpleFileVisitor<Path> {
         return FileVisitResult.CONTINUE;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see java.nio.file.SimpleFileVisitor#visitFile(java.lang.Object,
-     * java.nio.file.attribute.BasicFileAttributes)
-     */
     @Override
     public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
             throws IOException {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractAggregatorFactory.java b/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractAggregatorFactory.java
index 2d0778defd..d7b37741cf 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractAggregatorFactory.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractAggregatorFactory.java
@@ -39,38 +39,18 @@ public abstract class AbstractAggregatorFactory implements AggregatorFactory {
 
     protected abstract Aggregator createAggregator();
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregatorFactory#
-     * createValueAggregator(double)
-     */
     @Override
     public final Aggregator createValueAggregator() {
         return createAggregator();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.core.GraphAggregatorFactory#createKeyAggregator
-     * ()
-     */
     @Override
     public final Aggregator createKeyAggregator() {
         return createAggregator();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregatorFactory#
-     * createAggregatedKeyValueAggregator()
-     */
     @Override
     public final Aggregator createAggregatedKeyValueAggregator() {
         return createAggregator();
     }
-
 }
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSampleProcessor.java b/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSampleProcessor.java
index a0e40d31f4..0678721eed 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSampleProcessor.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSampleProcessor.java
@@ -32,24 +32,11 @@ public class AbstractSampleProcessor implements SampleProcessor {
 
     private final ArrayList<ChannelContext> channelContexts = new ArrayList<>();
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleProcessor#getSampleContext()
-     */
     @Override
     public SampleContext getSampleContext() {
         return sampleContext;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleProcessor#setSampleContext
-     * (org.apache.jmeter.report.csv.processor.SampleContext)
-     */
     @Override
     public void setSampleContext(SampleContext sampleContext) {
         this.sampleContext = sampleContext;
@@ -71,25 +58,11 @@ public class AbstractSampleProcessor implements SampleProcessor {
         return channelContexts.get(channel);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleProcessor#setChannelAttribute
-     * (int, java.lang.String, java.lang.Object)
-     */
     @Override
     public void setChannelAttribute(int channel, String key, Object value) {
         getChannelContext(channel).put(key, value);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleProcessor#getChannelAttribute
-     * (int, java.lang.String)
-     */
     @Override
     public Object getChannelAttribute(int channel, String key) {
         return getChannelContext(channel).get(key);
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSampleSource.java b/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSampleSource.java
index f8b38d680f..54b7e85bfa 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSampleSource.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSampleSource.java
@@ -33,63 +33,25 @@ public abstract class AbstractSampleSource implements SampleSource {
     protected AbstractSampleSource() {
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see java.lang.Runnable#run()
-     */
     @Override
     public abstract void run();
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.SampleSource#getSampleContext()
-     */
     @Override
     public SampleContext getSampleContext() {
         return sampleContext;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.SampleSource#setSampleContext(org.
-     * apache.jmeter.report.processor.SampleContext)
-     */
     @Override
     public void setSampleContext(SampleContext sampleContext) {
         this.sampleContext = sampleContext;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.SampleSource#addSampleConsumers(java
-     * .util.List)
-     */
     @Override
     public abstract void setSampleConsumers(List<SampleConsumer> consumers);
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.SampleSource#addSampleConsumer(org
-     * .apache.jmeter.report.processor.SampleConsumer)
-     */
     @Override
     public abstract void addSampleConsumer(SampleConsumer consumer);
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.SampleSource#removeSampleConsumer(
-     * org.apache.jmeter.report.processor.SampleConsumer)
-     */
     @Override
     public abstract void removeSampleConsumer(SampleConsumer consumer);
 
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSummaryConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSummaryConsumer.java
index b0beb8cd5f..0a63891d93 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSummaryConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/AbstractSummaryConsumer.java
@@ -202,11 +202,6 @@ public abstract class AbstractSummaryConsumer<TData> extends
         return result;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.SampleConsumer#startConsuming()
-     */
     @Override
     public void startConsuming() {
 
@@ -218,13 +213,6 @@ public abstract class AbstractSummaryConsumer<TData> extends
         super.startProducing();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.SampleConsumer#consume(org.apache.
-     * jmeter.report.core.Sample, int)
-     */
     @Override
     public void consume(Sample sample, int channel) {
         String key = getKeyFromSample(sample);
@@ -240,11 +228,6 @@ public abstract class AbstractSummaryConsumer<TData> extends
         super.produce(sample, channel);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.SampleConsumer#stopConsuming()
-     */
     @Override
     public void stopConsuming() {
         MapResultData result = new MapResultData();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/AggregateConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/AggregateConsumer.java
index 8462583383..7e9102be25 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/AggregateConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/AggregateConsumer.java
@@ -71,11 +71,6 @@ public class AggregateConsumer extends AbstractSampleConsumer {
         this.selector = selector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.SampleConsumer#startConsuming()
-     */
     @Override
     public void startConsuming() {
         // Broadcast metadata to consumes for each channel
@@ -87,24 +82,12 @@ public class AggregateConsumer extends AbstractSampleConsumer {
         super.startProducing();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.SampleConsumer#consume(org.apache.
-     * jmeter.report.core.Sample, int)
-     */
     @Override
     public void consume(Sample sample, int channel) {
         aggregator.addValue(selector.select(sample));
         super.produce(sample, channel);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.SampleConsumer#stopConsuming()
-     */
     @Override
     public void stopConsuming() {
         setDataToContext(getName(), new ValueResultData(aggregator.getResult()));
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/ApdexSummaryConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/ApdexSummaryConsumer.java
index 72f1f703a3..1d4625c16a 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/ApdexSummaryConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/ApdexSummaryConsumer.java
@@ -66,26 +66,11 @@ public class ApdexSummaryConsumer extends
         return result;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#getKeyFromSample
-     * (org.apache.jmeter.report.core.Sample)
-     */
     @Override
     protected String getKeyFromSample(Sample sample) {
         return sample.getName();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#updateData
-     * (org.apache.jmeter.report.processor.AbstractSummaryConsumer.SummaryInfo,
-     * org.apache.jmeter.report.core.Sample)
-     */
     @Override
     protected void updateData(SummaryInfo info, Sample sample) {
         if(sample.isEmptyController()) {
@@ -144,13 +129,6 @@ public class ApdexSummaryConsumer extends
                 / data.getTotalCount();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#createResultTitles
-     * ()
-     */
     @Override
     protected ListResultData createResultTitles() {
         ListResultData titles = new ListResultData();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/CsvFileSampleSource.java b/src/core/src/main/java/org/apache/jmeter/report/processor/CsvFileSampleSource.java
index 0ccca5a3a0..733591629a 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/CsvFileSampleSource.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/CsvFileSampleSource.java
@@ -191,37 +191,16 @@ public class CsvFileSampleSource extends AbstractSampleSource {
         }
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSampleSource#addSampleConsumers
-     * (java.util.List)
-     */
     @Override
     public void setSampleConsumers(List<SampleConsumer> consumers) {
         producer.setSampleConsumers(consumers);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSampleSource#addSampleConsumer
-     * (org.apache.jmeter.report.processor.SampleConsumer)
-     */
     @Override
     public void addSampleConsumer(SampleConsumer consumer) {
         producer.addSampleConsumer(consumer);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSampleSource#removeSampleConsumer
-     * (org.apache.jmeter.report.processor.SampleConsumer)
-     */
     @Override
     public void removeSampleConsumer(SampleConsumer consumer) {
         producer.removeSampleConsumer(consumer);
@@ -248,20 +227,20 @@ public class CsvFileSampleSource extends AbstractSampleSource {
          * @param consumers list of consumers for the samples (must not be
          *                  {@code null})
          */
-        public void setSampleConsumers(List<SampleConsumer> consumers) {
+        private void setSampleConsumers(List<SampleConsumer> consumers) {
             Objects.requireNonNull(consumers, "consumers must not be null");
 
             this.sampleConsumers = consumers;
         }
 
-        public void addSampleConsumer(SampleConsumer consumer) {
+        private void addSampleConsumer(SampleConsumer consumer) {
             if (consumer == null) {
                 return;
             }
             this.sampleConsumers.add(consumer);
         }
 
-        public void removeSampleConsumer(SampleConsumer consumer) {
+        private void removeSampleConsumer(SampleConsumer consumer) {
             if (consumer == null) {
                 return;
             }
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumer.java
index 139680380a..ad3bcbc669 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumer.java
@@ -52,13 +52,6 @@ public class ErrorsSummaryConsumer extends AbstractSummaryConsumer<Long> {
         super(false);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#createDataResult
-     * (java.lang.String)
-     */
     @Override
     protected ListResultData createDataResult(String key, Long data) {
         ListResultData result = new ListResultData();
@@ -71,13 +64,6 @@ public class ErrorsSummaryConsumer extends AbstractSummaryConsumer<Long> {
         return result;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#getKeyFromSample
-     * (org.apache.jmeter.report.core.Sample)
-     */
     @Override
     protected String getKeyFromSample(Sample sample) {
         return getErrorKey(sample);
@@ -114,14 +100,6 @@ public class ErrorsSummaryConsumer extends AbstractSummaryConsumer<Long> {
         return new String(JsonStringEncoder.getInstance().quoteAsString(StringEscapeUtils.escapeHtml4(responseMessage)));
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#updateData
-     * (org.apache.jmeter.report.processor.AbstractSummaryConsumer.SummaryInfo,
-     * org.apache.jmeter.report.core.Sample)
-     */
     @Override
     protected void updateData(SummaryInfo info, Sample sample) {
         // Initialize overall data if they don't exist
@@ -144,11 +122,6 @@ public class ErrorsSummaryConsumer extends AbstractSummaryConsumer<Long> {
         }
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.SampleConsumer#stopConsuming()
-     */
     @Override
     public void stopConsuming() {
         super.stopConsuming();
@@ -157,13 +130,6 @@ public class ErrorsSummaryConsumer extends AbstractSummaryConsumer<Long> {
         errorCount = 0L;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#createResultTitles
-     * ()
-     */
     @Override
     protected ListResultData createResultTitles() {
         ListResultData titles = new ListResultData();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/ListResultData.java b/src/core/src/main/java/org/apache/jmeter/report/processor/ListResultData.java
index da674ee080..37de195ea2 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/ListResultData.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/ListResultData.java
@@ -30,13 +30,6 @@ public class ListResultData implements ResultData, Iterable<ResultData> {
 
     private final List<ResultData> items = new ArrayList<>();
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.ResultData#accept(org.apache.jmeter
-     * .report.processor.ResultDataVisitor)
-     */
     @Override
     public <T> T accept(ResultDataVisitor<T> visitor) {
         return visitor.visitListResult(this);
@@ -81,19 +74,11 @@ public class ListResultData implements ResultData, Iterable<ResultData> {
         return items.size();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see java.lang.Iterable#iterator()
-     */
     @Override
     public Iterator<ResultData> iterator() {
         return items.iterator();
     }
 
-    /* (non-Javadoc)
-     * @see java.lang.Object#toString()
-     */
     @Override
     public String toString() {
         return "ListResultData [items=" + items + "]";
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/MapResultData.java b/src/core/src/main/java/org/apache/jmeter/report/processor/MapResultData.java
index c52c89b355..2984e8d36b 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/MapResultData.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/MapResultData.java
@@ -31,13 +31,6 @@ public class MapResultData implements ResultData {
 
     private final Map<String, ResultData> map = new HashMap<>();
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.ResultData#accept(org.apache.jmeter
-     * .report.processor.ResultDataVisitor)
-     */
     @Override
     public <T> T accept(ResultDataVisitor<T> visitor) {
         return visitor.visitMapResult(this);
@@ -87,9 +80,6 @@ public class MapResultData implements ResultData {
         return map.remove(name);
     }
 
-    /* (non-Javadoc)
-     * @see java.lang.Object#toString()
-     */
     @Override
     public String toString() {
         return "MapResultData [map=" + map + "]";
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/MaxAggregator.java b/src/core/src/main/java/org/apache/jmeter/report/processor/MaxAggregator.java
index 7ceb2e712c..23c3de2f25 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/MaxAggregator.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/MaxAggregator.java
@@ -27,42 +27,22 @@ public class MaxAggregator implements Aggregator {
     private long count = 0L;
     private double value = Double.MIN_VALUE;
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getCount()
-     */
     @Override
     public long getCount() {
         return count;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getResult()
-     */
     @Override
     public double getResult() {
         return value;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#addValue(double)
-     */
     @Override
     public void addValue(double value) {
         this.value = Math.max(this.value, value);
         count++;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#reset()
-     */
     @Override
     public void reset() {
         count = 0L;
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/MaxAggregatorFactory.java b/src/core/src/main/java/org/apache/jmeter/report/processor/MaxAggregatorFactory.java
index c839b822f2..4f4643a9c9 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/MaxAggregatorFactory.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/MaxAggregatorFactory.java
@@ -25,13 +25,6 @@ package org.apache.jmeter.report.processor;
 public class MaxAggregatorFactory extends AbstractAggregatorFactory {
 
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.core.AbstractAggregatorFactory#createAggregator
-     * ()
-     */
     @Override
     protected Aggregator createAggregator() {
         return new MaxAggregator();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/MeanAggregator.java b/src/core/src/main/java/org/apache/jmeter/report/processor/MeanAggregator.java
index 3258f94631..ac7d60dcf0 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/MeanAggregator.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/MeanAggregator.java
@@ -28,41 +28,21 @@ public class MeanAggregator implements Aggregator {
 
     private final Mean mean = new Mean();
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getCount()
-     */
     @Override
     public long getCount() {
         return mean.getN();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getResult()
-     */
     @Override
     public double getResult() {
         return mean.getResult();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#addValue(double)
-     */
     @Override
     public void addValue(double value) {
         mean.increment(value);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#reset()
-     */
     @Override
     public void reset() {
         mean.clear();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/MeanAggregatorFactory.java b/src/core/src/main/java/org/apache/jmeter/report/processor/MeanAggregatorFactory.java
index 7b56904e7d..96bffbbee7 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/MeanAggregatorFactory.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/MeanAggregatorFactory.java
@@ -24,13 +24,6 @@ package org.apache.jmeter.report.processor;
  */
 public class MeanAggregatorFactory extends AbstractAggregatorFactory {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.core.AbstractAggregatorFactory#createAggregator
-     * ()
-     */
     @Override
     protected Aggregator createAggregator() {
         return new MeanAggregator();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/MedianAggregatorFactory.java b/src/core/src/main/java/org/apache/jmeter/report/processor/MedianAggregatorFactory.java
index 4430c44f26..36e6659419 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/MedianAggregatorFactory.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/MedianAggregatorFactory.java
@@ -25,13 +25,6 @@ package org.apache.jmeter.report.processor;
  */
 public class MedianAggregatorFactory extends AbstractAggregatorFactory {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.core.AbstractAggregatorFactory#createAggregator
-     * ()
-     */
     @Override
     protected Aggregator createAggregator() {
         return new PercentileAggregator(50);
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/MinAggregator.java b/src/core/src/main/java/org/apache/jmeter/report/processor/MinAggregator.java
index d020c4099e..ec7954e216 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/MinAggregator.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/MinAggregator.java
@@ -27,42 +27,22 @@ public class MinAggregator implements Aggregator {
     private long count = 0L;
     private double value = Double.MAX_VALUE;
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getCount()
-     */
     @Override
     public long getCount() {
         return count;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getResult()
-     */
     @Override
     public double getResult() {
         return value;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#addValue(double)
-     */
     @Override
     public void addValue(double value) {
         this.value = Math.min(this.value, value);
         count++;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#reset()
-     */
     @Override
     public void reset() {
         count = 0L;
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/PercentileAggregator.java b/src/core/src/main/java/org/apache/jmeter/report/processor/PercentileAggregator.java
index ca81b2ebf7..424d123f35 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/PercentileAggregator.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/PercentileAggregator.java
@@ -54,41 +54,21 @@ public class PercentileAggregator implements Aggregator {
         this.percentileIndex = lastAggregator.percentileIndex;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getCount()
-     */
     @Override
     public long getCount() {
         return statistics.getN();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getResult()
-     */
     @Override
     public double getResult() {
         return statistics.getPercentile(percentileIndex);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#addValue(double)
-     */
     @Override
     public void addValue(double value) {
         statistics.addValue(value);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#reset()
-     */
     @Override
     public void reset() {
         statistics.clear();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/PercentileAggregatorFactory.java b/src/core/src/main/java/org/apache/jmeter/report/processor/PercentileAggregatorFactory.java
index d79a62660c..5fd35799ae 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/PercentileAggregatorFactory.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/PercentileAggregatorFactory.java
@@ -46,13 +46,6 @@ public class PercentileAggregatorFactory extends AbstractAggregatorFactory {
         this.percentileIndex = percentileIndex;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.core.AbstractAggregatorFactory#createAggregator
-     * ()
-     */
     @Override
     protected Aggregator createAggregator() {
         Aggregator newAggregator = null;
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/RequestsSummaryConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/RequestsSummaryConsumer.java
index a925cab116..9e991868fc 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/RequestsSummaryConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/RequestsSummaryConsumer.java
@@ -32,9 +32,6 @@ public class RequestsSummaryConsumer extends AbstractSampleConsumer {
     private long count;
     private long errorCount;
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.report.processor.SampleConsumer#startConsuming()
-     */
     @Override
     public void startConsuming() {
         count = 0L;
@@ -49,9 +46,6 @@ public class RequestsSummaryConsumer extends AbstractSampleConsumer {
         super.startProducing();
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.report.processor.SampleConsumer#consume(org.apache.jmeter.report.core.Sample, int)
-     */
     @Override
     public void consume(Sample sample, int channel) {
         if(!sample.isController()) {
@@ -63,11 +57,6 @@ public class RequestsSummaryConsumer extends AbstractSampleConsumer {
         super.produce(sample, channel);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.SampleConsumer#stopConsuming()
-     */
     @Override
     public void stopConsuming() {
         MapResultData result = new MapResultData();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/StatisticsSummaryConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/StatisticsSummaryConsumer.java
index 6125efa29a..a790e910de 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/StatisticsSummaryConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/StatisticsSummaryConsumer.java
@@ -94,14 +94,6 @@ public class StatisticsSummaryConsumer extends
         data.setEndTime(sample.getEndTime());
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#updateData
-     * (org.apache.jmeter.report.processor.AbstractSummaryConsumer.SummaryInfo,
-     * org.apache.jmeter.report.core.Sample)
-     */
     @Override
     protected void updateData(SummaryInfo info, Sample sample) {
         SummaryInfo overallInfo = getOverallInfo();
@@ -125,13 +117,6 @@ public class StatisticsSummaryConsumer extends
         }
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#createDataResult
-     * (java.lang.String)
-     */
     @Override
     protected ListResultData createDataResult(String key,
             StatisticsSummaryData data) {
@@ -156,25 +141,11 @@ public class StatisticsSummaryConsumer extends
         return result;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#getKeyFromSample
-     * (org.apache.jmeter.report.core.Sample)
-     */
     @Override
     protected String getKeyFromSample(Sample sample) {
         return sample.getName();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#createResultTitles
-     * ()
-     */
     @Override
     protected ListResultData createResultTitles() {
         ListResultData titles = new ListResultData();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/SumAggregator.java b/src/core/src/main/java/org/apache/jmeter/report/processor/SumAggregator.java
index 3f5cf10f7b..5db5d3d733 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/SumAggregator.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/SumAggregator.java
@@ -27,42 +27,22 @@ public class SumAggregator implements Aggregator {
     private long count = 0;
     private double sum = 0;
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getCount()
-     */
     @Override
     public long getCount() {
         return count;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getResult()
-     */
     @Override
     public double getResult() {
         return sum;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#addValue(double)
-     */
     @Override
     public void addValue(double value) {
         count++;
         sum += value;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#reset()
-     */
     @Override
     public void reset() {
         count = 0;
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/SumAggregatorFactory.java b/src/core/src/main/java/org/apache/jmeter/report/processor/SumAggregatorFactory.java
index 3d74f00f16..4155fbf4f8 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/SumAggregatorFactory.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/SumAggregatorFactory.java
@@ -24,13 +24,6 @@ package org.apache.jmeter.report.processor;
  */
 public class SumAggregatorFactory extends AbstractAggregatorFactory {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.core.AbstractAggregatorFactory#createAggregator
-     * ()
-     */
     @Override
     protected Aggregator createAggregator() {
         return new SumAggregator();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/TimeRateAggregator.java b/src/core/src/main/java/org/apache/jmeter/report/processor/TimeRateAggregator.java
index aa090c1206..ea4aeedb0b 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/TimeRateAggregator.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/TimeRateAggregator.java
@@ -43,42 +43,22 @@ public class TimeRateAggregator implements Aggregator {
         this.granularity = granularity;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getCount()
-     */
     @Override
     public long getCount() {
         return count;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#getResult()
-     */
     @Override
     public double getResult() {
         return value * 1000 / granularity;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#addValue(double)
-     */
     @Override
     public void addValue(final double value) {
         this.count++;
         this.value += value;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.core.GraphAggregator#reset()
-     */
     @Override
     public void reset() {
         count = 0;
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/TimeRateAggregatorFactory.java b/src/core/src/main/java/org/apache/jmeter/report/processor/TimeRateAggregatorFactory.java
index 1a81168058..8f300d3463 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/TimeRateAggregatorFactory.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/TimeRateAggregatorFactory.java
@@ -45,13 +45,6 @@ public class TimeRateAggregatorFactory extends AbstractAggregatorFactory {
         this.granularity = granularity;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.core.AbstractAggregatorFactory#createAggregator
-     * ()
-     */
     @Override
     protected Aggregator createAggregator() {
         TimeRateAggregator aggregator = new TimeRateAggregator();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/Top5ErrorsBySamplerConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/Top5ErrorsBySamplerConsumer.java
index b73efbeaf8..8ffe791666 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/Top5ErrorsBySamplerConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/Top5ErrorsBySamplerConsumer.java
@@ -76,13 +76,6 @@ public class Top5ErrorsBySamplerConsumer extends
         }
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#createDataResult
-     * (java.lang.String)
-     */
     @Override
     protected ListResultData createDataResult(String key, Top5ErrorsSummaryData data) {
         ListResultData result = new ListResultData();
@@ -110,25 +103,11 @@ public class Top5ErrorsBySamplerConsumer extends
         return result;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#getKeyFromSample
-     * (org.apache.jmeter.report.core.Sample)
-     */
     @Override
     protected String getKeyFromSample(Sample sample) {
         return sample.getName();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSummaryConsumer#createResultTitles
-     * ()
-     */
     @Override
     protected ListResultData createResultTitles() {
         ListResultData titles = new ListResultData();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/ValueResultData.java b/src/core/src/main/java/org/apache/jmeter/report/processor/ValueResultData.java
index 5d81a32613..054ff0bbd3 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/ValueResultData.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/ValueResultData.java
@@ -41,21 +41,11 @@ public class ValueResultData implements ResultData {
         this.value = value;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.ResultData#accept(org.apache.jmeter
-     * .report.processor.ResultDataVisitor)
-     */
     @Override
     public <T> T accept(ResultDataVisitor<T> visitor) {
         return visitor.visitValueResult(this);
     }
 
-    /* (non-Javadoc)
-     * @see java.lang.Object#toString()
-     */
     @Override
     public String toString() {
         return "ValueResultData [value=" + value + "]";
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractGraphConsumer.java
index 673722df7e..7863913127 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractGraphConsumer.java
@@ -314,7 +314,7 @@ public abstract class AbstractGraphConsumer extends AbstractSampleConsumer {
                 for (Map.Entry<Double, Aggregator> entry : sortedInfo
                         .entrySet()) {
                     Double value = entry.getKey();
-                    percent += (double) 100 * entry.getValue().getCount()
+                    percent += 100.0 * entry.getValue().getCount()
                             / count;
                     double percentile = (double) rank / 10;
                     while (percentile < percent) {
@@ -334,7 +334,7 @@ public abstract class AbstractGraphConsumer extends AbstractSampleConsumer {
                 for (Map.Entry<Double, Aggregator> entry : sortedInfo
                         .entrySet()) {
                     Double value = entry.getKey();
-                    percent += (double) 100 * entry.getValue().getCount()
+                    percent += 100.0 * entry.getValue().getCount()
                             / count;
                     double percentile = (double) rank / 10;
                     while (percentile < percent) {
@@ -439,12 +439,6 @@ public abstract class AbstractGraphConsumer extends AbstractSampleConsumer {
      */
     protected abstract void initializeExtraResults(MapResultData parentResult);
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleConsumer#startConsuming()
-     */
     @Override
     public void startConsuming() {
 
@@ -457,13 +451,6 @@ public abstract class AbstractGraphConsumer extends AbstractSampleConsumer {
         super.startProducing();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleConsumer#consume(org.apache
-     * .jmeter.report.csv.core.Sample, int)
-     */
     @Override
     public void consume(Sample sample, int channel) {
 
@@ -513,18 +500,6 @@ public abstract class AbstractGraphConsumer extends AbstractSampleConsumer {
         super.produce(sample, channel);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleConsumer#stopConsuming()
-     */
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.graph.SampleConsumer#stopConsuming()
-     */
     @Override
     public void stopConsuming() {
         super.stopProducing();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractOverTimeGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractOverTimeGraphConsumer.java
index a04d935873..aedb0659e8 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractOverTimeGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractOverTimeGraphConsumer.java
@@ -67,12 +67,6 @@ public abstract class AbstractOverTimeGraphConsumer extends
      */
     protected abstract TimeStampKeysSelector createTimeStampKeysSelector();
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createKeysSelector()
-     */
     @Override
     protected final GraphKeysSelector createKeysSelector() {
         TimeStampKeysSelector keysSelector = createTimeStampKeysSelector();
@@ -80,21 +74,9 @@ public abstract class AbstractOverTimeGraphConsumer extends
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected abstract Map<String, GroupInfo> createGroupInfos();
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * initializeExtraResults(org.apache.jmeter.report.processor.MapResultData)
-     */
     @Override
     protected void initializeExtraResults(MapResultData parentResult) {
         parentResult.setResult(RESULT_CTX_GRANULARITY, new ValueResultData(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractSeriesSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractSeriesSelector.java
index ce812820f4..673a47c4dc 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractSeriesSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractSeriesSelector.java
@@ -50,12 +50,6 @@ public abstract class AbstractSeriesSelector implements GraphSeriesSelector {
         this.allowsControllerDiscrimination = allowsControllerDiscrimination;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.GraphSeriesSelector#
-     * supportsControllersDiscrimination()
-     */
     @Override
     public final boolean allowsControllersDiscrimination() {
         return allowsControllerDiscrimination;
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractVersusRequestsGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractVersusRequestsGraphConsumer.java
index 59202d113d..1b73441c02 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractVersusRequestsGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/AbstractVersusRequestsGraphConsumer.java
@@ -21,6 +21,7 @@ import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.apache.commons.io.FileUtils;
@@ -82,13 +83,6 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
     protected AbstractVersusRequestsGraphConsumer() {
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#startConsuming
-     * ()
-     */
     @Override
     public void startConsuming() {
         embeddedConsumer.startConsuming();
@@ -105,13 +99,6 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
         super.startConsuming();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.AbstractSampleConsumer#setConsumedMetadata
-     * (org.apache.jmeter.report.core.SampleMetadata, int)
-     */
     @Override
     public void setConsumedMetadata(SampleMetadata sampleMetadata, int channel) {
         embeddedConsumer.setConsumedMetadata(sampleMetadata, channel);
@@ -122,13 +109,6 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
         super.setConsumedMetadata(sampleMetadata, channel);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#consume
-     * (org.apache.jmeter.report.core.Sample, int)
-     */
     @Override
     public void consume(Sample sample, int channel) {
         embeddedConsumer.consume(sample, channel);
@@ -138,13 +118,6 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
         super.consume(sample, channel);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#stopConsuming
-     * ()
-     */
     @Override
     public void stopConsuming() {
         embeddedConsumer.stopConsuming();
@@ -154,12 +127,6 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
         super.stopConsuming();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * initializeExtraResults(org.apache.jmeter.report.processor.MapResultData)
-     */
     @Override
     protected void initializeExtraResults(MapResultData parentResult) {
         parentResult.setResult(RESULT_CTX_GRANULARITY, new ValueResultData(
@@ -182,7 +149,7 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
              * @param metadata
              *            the metadata
              */
-            public FileInfo(File file, SampleMetadata metadata) {
+            private FileInfo(File file, SampleMetadata metadata) {
                 this.file = file;
                 this.writer = new CsvSampleWriter(file, metadata);
             }
@@ -192,7 +159,7 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
              *
              * @return the file
              */
-            public File getFile() {
+            private File getFile() {
                 return file;
             }
 
@@ -201,19 +168,19 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
              *
              * @return the sample writer
              */
-            public CsvSampleWriter getWriter() {
+            private CsvSampleWriter getWriter() {
                 return writer;
             }
         }
 
         // Collection of sample builders for channels
-        private final ArrayList<SampleBuilder> builders = new ArrayList<>();
-        private final ArrayList<FileInfo> fileInfos = new ArrayList<>();
+        private final List<SampleBuilder> builders = new ArrayList<>();
+        private final List<FileInfo> fileInfos = new ArrayList<>();
         private final Map<Long, Long> counts = new HashMap<>();
         boolean createdWorkDir = false;
         private final AbstractVersusRequestsGraphConsumer parent;
 
-        public TimeCountConsumer(AbstractVersusRequestsGraphConsumer parent) {
+        private TimeCountConsumer(AbstractVersusRequestsGraphConsumer parent) {
             this.parent = parent;
         }
 
@@ -299,13 +266,6 @@ public abstract class AbstractVersusRequestsGraphConsumer extends
             initProducedMetadata();
         }
 
-        /*
-         * (non-Javadoc)
-         *
-         * @see
-         * org.apache.jmeter.report.processor.SampleConsumer#consume(org.apache.
-         * jmeter.report.core.Sample, int)
-         */
         @Override
         public void consume(Sample sample, int channel) {
             // Count sample depending on time interval
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/CodeSeriesSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/CodeSeriesSelector.java
index a959a3c37c..c54a88c811 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/CodeSeriesSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/CodeSeriesSelector.java
@@ -27,13 +27,6 @@ import org.apache.jmeter.report.core.Sample;
  */
 public class CodeSeriesSelector extends AbstractSeriesSelector {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleSelector#select(org.apache
-     * .jmeter.report.csv.core.Sample)
-     */
     @Override
     public Iterable<String> select(Sample sample) {
         return withDefaultIfEmpty(sample.getResponseCode(), "EMPTY_RES_CODE"); //$NON-NLS-1$
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/ConnectTimeValueSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/ConnectTimeValueSelector.java
index 1057063752..dcd2738120 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/ConnectTimeValueSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/ConnectTimeValueSelector.java
@@ -35,13 +35,6 @@ public class ConnectTimeValueSelector extends AbstractGraphValueSelector {
         super(ignoreTransactionController);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.GraphValueSelector#select(java
-     * .lang.String, java.lang.Object, org.apache.jmeter.report.csv.core.Sample)
-     */
     @Override
     public Double select(String series, Sample sample) {
         if(isIgnoreTransactionController()) {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/ElapsedTimeValueSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/ElapsedTimeValueSelector.java
index 5299a3dcea..081c5425cd 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/ElapsedTimeValueSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/ElapsedTimeValueSelector.java
@@ -36,11 +36,6 @@ public class ElapsedTimeValueSelector extends AbstractGraphValueSelector {
         super(ignoreTransactionController);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see GraphValueSelector#select(String, Sample)
-     */
     @Override
     public Double select(String series, Sample sample) {
         if(isIgnoreTransactionController()) {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/IndexedNameSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/IndexedNameSelector.java
index 21a8bb27b8..a82ee0f614 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/IndexedNameSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/IndexedNameSelector.java
@@ -42,13 +42,6 @@ public class IndexedNameSelector implements GraphKeysSelector {
         return names;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleSelector#select(org.apache
-     * .jmeter.report.csv.core.Sample)
-     */
     @Override
     public Double select(Sample sample) {
         String name = sample.getName();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/LatencyValueSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/LatencyValueSelector.java
index 75192b60a5..a42c490820 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/LatencyValueSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/LatencyValueSelector.java
@@ -35,13 +35,6 @@ public class LatencyValueSelector extends AbstractGraphValueSelector {
         super(ignoreTransactionController);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.GraphValueSelector#select(java
-     * .lang.String, java.lang.Object, org.apache.jmeter.report.csv.core.Sample)
-     */
     @Override
     public Double select(String series, Sample sample) {
         if(isIgnoreTransactionController()) {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/NameSeriesSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/NameSeriesSelector.java
index 490c95b6e2..b4cdce6e54 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/NameSeriesSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/NameSeriesSelector.java
@@ -33,13 +33,6 @@ public class NameSeriesSelector extends AbstractSeriesSelector {
         super(true);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleSelector#select(org.apache
-     * .jmeter.report.csv.core.Sample)
-     */
     @Override
     public Iterable<String> select(Sample sample) {
         return withDefaultIfEmpty(sample.getName(), "EMPTY_SERIE_NAME"); //$NON-NLS-1$
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/StaticSeriesSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/StaticSeriesSelector.java
index 0e6a6f4852..fc07ab127f 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/StaticSeriesSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/StaticSeriesSelector.java
@@ -47,13 +47,6 @@ public class StaticSeriesSelector extends AbstractSeriesSelector {
         this.seriesName = seriesName;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleSelector#select(org.apache
-     * .jmeter.report.csv.core.Sample)
-     */
     @Override
     public Iterable<String> select(Sample sample) {
         return withDefaultIfEmpty(seriesName, "EMPTY_SERIE_NAME"); //$NON-NLS-1$
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/StatusSeriesSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/StatusSeriesSelector.java
index ffd56f39c2..bbd5957a29 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/StatusSeriesSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/StatusSeriesSelector.java
@@ -70,13 +70,6 @@ public class StatusSeriesSelector extends AbstractSeriesSelector {
         this.successLabel = successLabel;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.SampleSelector#select(org.apache
-     * .jmeter.report.csv.core.Sample)
-     */
     @Override
     public Iterable<String> select(Sample sample) {
         String label = sample.getSuccess() ? successLabel : failureLabel;
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/TimeStampKeysSelector.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/TimeStampKeysSelector.java
index b3a2881580..249c972612 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/TimeStampKeysSelector.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/TimeStampKeysSelector.java
@@ -70,13 +70,6 @@ public class TimeStampKeysSelector implements GraphKeysSelector {
         this.selectBeginTime = selectBeginTime;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.core.SampleSelector#select(org.apache.jmeter
-     * .report.core.Sample)
-     */
     @Override
     public Double select(Sample sample) {
         long time = selectBeginTime ? sample.getStartTime() : sample.getEndTime();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ActiveThreadsGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ActiveThreadsGraphConsumer.java
index a62f86e3c6..1596fc9c63 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ActiveThreadsGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ActiveThreadsGraphConsumer.java
@@ -37,13 +37,6 @@ import org.apache.jmeter.report.processor.graph.TimeStampKeysSelector;
  */
 public class ActiveThreadsGraphConsumer extends AbstractOverTimeGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -51,12 +44,6 @@ public class ActiveThreadsGraphConsumer extends AbstractOverTimeGraphConsumer {
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         AbstractSeriesSelector seriesSelector = new AbstractSeriesSelector() {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/BytesThroughputGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/BytesThroughputGraphConsumer.java
index 240d93cdbf..6ae0ab58a8 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/BytesThroughputGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/BytesThroughputGraphConsumer.java
@@ -41,13 +41,6 @@ public class BytesThroughputGraphConsumer extends AbstractOverTimeGraphConsumer
     private static final String RECEIVED_BYTES_SERIES_LABEL = "Bytes received per second";
     private static final String SENT_BYTES_SERIES_LABEL = "Bytes sent per second";
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -55,12 +48,6 @@ public class BytesThroughputGraphConsumer extends AbstractOverTimeGraphConsumer
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         AbstractSeriesSelector seriesSelector = new AbstractSeriesSelector() {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/CodesPerSecondGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/CodesPerSecondGraphConsumer.java
index 2e4f3a4102..ec76635c65 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/CodesPerSecondGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/CodesPerSecondGraphConsumer.java
@@ -36,13 +36,6 @@ import org.apache.jmeter.report.processor.graph.TimeStampKeysSelector;
  */
 public class CodesPerSecondGraphConsumer extends AbstractOverTimeGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -50,12 +43,6 @@ public class CodesPerSecondGraphConsumer extends AbstractOverTimeGraphConsumer {
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ConnectTimeOverTimeGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ConnectTimeOverTimeGraphConsumer.java
index 698d3a3b80..71771e6d35 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ConnectTimeOverTimeGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ConnectTimeOverTimeGraphConsumer.java
@@ -39,13 +39,6 @@ public class ConnectTimeOverTimeGraphConsumer extends AbstractOverTimeGraphConsu
     private static final boolean CONNECT_TIME_SAVED =
             JMeterUtils.getPropDefault("jmeter.save.saveservice.connect_time", true); //$NON-NLS-1$
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -53,12 +46,6 @@ public class ConnectTimeOverTimeGraphConsumer extends AbstractOverTimeGraphConsu
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         if (!CONNECT_TIME_SAVED) {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/CustomGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/CustomGraphConsumer.java
index 72420a3585..0585b1b5be 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/CustomGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/CustomGraphConsumer.java
@@ -169,13 +169,6 @@ public class CustomGraphConsumer extends AbstractOverTimeGraphConsumer implement
         parentResult.setResult(RESULT_CONTENT_MESSAGE, new ValueResultData(getContentMessage()));
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -183,12 +176,6 @@ public class CustomGraphConsumer extends AbstractOverTimeGraphConsumer implement
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         AbstractSeriesSelector seriesSelector = new AbstractSeriesSelector() {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/HitsPerSecondGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/HitsPerSecondGraphConsumer.java
index 0d5828bd6d..a4873bf741 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/HitsPerSecondGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/HitsPerSecondGraphConsumer.java
@@ -36,13 +36,6 @@ import org.apache.jmeter.report.processor.graph.TimeStampKeysSelector;
  */
 public class HitsPerSecondGraphConsumer extends AbstractOverTimeGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -50,12 +43,6 @@ public class HitsPerSecondGraphConsumer extends AbstractOverTimeGraphConsumer {
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/LatencyOverTimeGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/LatencyOverTimeGraphConsumer.java
index 73c5bb2356..15b9f61a08 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/LatencyOverTimeGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/LatencyOverTimeGraphConsumer.java
@@ -36,13 +36,6 @@ import org.apache.jmeter.report.processor.graph.TimeStampKeysSelector;
  */
 public class LatencyOverTimeGraphConsumer extends AbstractOverTimeGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -50,12 +43,6 @@ public class LatencyOverTimeGraphConsumer extends AbstractOverTimeGraphConsumer
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/LatencyVSRequestGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/LatencyVSRequestGraphConsumer.java
index 3adf21fb7a..fc396c3698 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/LatencyVSRequestGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/LatencyVSRequestGraphConsumer.java
@@ -37,12 +37,6 @@ import org.apache.jmeter.report.processor.graph.StatusSeriesSelector;
 public class LatencyVSRequestGraphConsumer extends
         AbstractVersusRequestsGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * createKeysSelector()
-     */
     @Override
     protected GraphKeysSelector createKeysSelector() {
         return sample ->
@@ -51,12 +45,6 @@ public class LatencyVSRequestGraphConsumer extends
                         AbstractVersusRequestsGraphConsumer.TIME_INTERVAL_LABEL);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseCustomGraphGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseCustomGraphGraphConsumer.java
index 1bfdb83df8..c6809fbb3d 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseCustomGraphGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseCustomGraphGraphConsumer.java
@@ -37,13 +37,6 @@ import org.apache.jmeter.report.processor.graph.TimeStampKeysSelector;
 public class ResponseCustomGraphGraphConsumer extends
         AbstractOverTimeGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -51,12 +44,6 @@ public class ResponseCustomGraphGraphConsumer extends
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeDistributionGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeDistributionGraphConsumer.java
index 0d83696948..3550213adf 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeDistributionGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeDistributionGraphConsumer.java
@@ -57,12 +57,6 @@ public class ResponseTimeDistributionGraphConsumer extends
         this.granularity = granularity;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createKeysSelector()
-     */
     @Override
     protected final GraphKeysSelector createKeysSelector() {
         return sample -> {
@@ -71,12 +65,6 @@ public class ResponseTimeDistributionGraphConsumer extends
         };
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
@@ -87,12 +75,6 @@ public class ResponseTimeDistributionGraphConsumer extends
                         new CountValueSelector(false), false, false));
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * initializeExtraResults(org.apache.jmeter.report.processor.MapResultData)
-     */
     @Override
     protected void initializeExtraResults(MapResultData parentResult) {
         parentResult.setResult(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeOverTimeGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeOverTimeGraphConsumer.java
index b07741fe70..1d94300c98 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeOverTimeGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeOverTimeGraphConsumer.java
@@ -37,13 +37,6 @@ import org.apache.jmeter.report.processor.graph.TimeStampKeysSelector;
 public class ResponseTimeOverTimeGraphConsumer extends
         AbstractOverTimeGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -51,12 +44,6 @@ public class ResponseTimeOverTimeGraphConsumer extends
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimePerSampleGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimePerSampleGraphConsumer.java
index 9872ccafb2..f0176e2a30 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimePerSampleGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimePerSampleGraphConsumer.java
@@ -53,12 +53,6 @@ public class ResponseTimePerSampleGraphConsumer extends AbstractGraphConsumer {
         setRevertKeysAndValues(true);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createKeysSelector()
-     */
     @Override
     protected final GraphKeysSelector createKeysSelector() {
         return new IndexedNameSelector();
@@ -85,12 +79,6 @@ public class ResponseTimePerSampleGraphConsumer extends AbstractGraphConsumer {
                 new ElapsedTimeValueSelector(false), false, false);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         HashMap<String, GroupInfo> groupInfos = new HashMap<>(6);
@@ -107,12 +95,6 @@ public class ResponseTimePerSampleGraphConsumer extends AbstractGraphConsumer {
         return groupInfos;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * initializeExtraResults(org.apache.jmeter.report.processor.MapResultData)
-     */
     @Override
     protected void initializeExtraResults(MapResultData parentResult) {
         ListResultData samples = new ListResultData();
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimePercentilesGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimePercentilesGraphConsumer.java
index a25b5141a4..f428df0932 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimePercentilesGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimePercentilesGraphConsumer.java
@@ -48,23 +48,11 @@ public class ResponseTimePercentilesGraphConsumer extends AbstractGraphConsumer
         setRenderPercentiles(true);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createKeysSelector()
-     */
     @Override
     protected final GraphKeysSelector createKeysSelector() {
         return sample -> (double) sample.getElapsedTime();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
@@ -75,12 +63,6 @@ public class ResponseTimePercentilesGraphConsumer extends AbstractGraphConsumer
                         new CountValueSelector(false), false, false));
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * initializeExtraResults(org.apache.jmeter.report.processor.MapResultData)
-     */
     @Override
     protected void initializeExtraResults(MapResultData parentResult) {
         // do nothing
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeVSRequestGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeVSRequestGraphConsumer.java
index fe4277aebf..35d8045001 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeVSRequestGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/ResponseTimeVSRequestGraphConsumer.java
@@ -37,24 +37,12 @@ import org.apache.jmeter.report.processor.graph.StatusSeriesSelector;
 public class ResponseTimeVSRequestGraphConsumer extends
         AbstractVersusRequestsGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * createKeysSelector()
-     */
     @Override
     protected GraphKeysSelector createKeysSelector() {
         return sample -> sample.getData(
                 Double.class, AbstractVersusRequestsGraphConsumer.TIME_INTERVAL_LABEL);
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/SyntheticResponseTimeDistributionGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/SyntheticResponseTimeDistributionGraphConsumer.java
index 8058f95093..ff2547c971 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/SyntheticResponseTimeDistributionGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/SyntheticResponseTimeDistributionGraphConsumer.java
@@ -80,19 +80,13 @@ public class SyntheticResponseTimeDistributionGraphConsumer extends
         }
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createKeysSelector()
-     */
     @Override
     protected final GraphKeysSelector createKeysSelector() {
         return sample -> {
             if (sample.getSuccess()) {
                 long elapsedTime = sample.getElapsedTime();
                 if (elapsedTime <= satisfiedThreshold) {
-                    return (double) 0;
+                    return 0d;
                 } else if (elapsedTime <= toleratedThreshold) {
                     return 1d;
                 } else {
@@ -104,12 +98,6 @@ public class SyntheticResponseTimeDistributionGraphConsumer extends
         };
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TimeVSThreadGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TimeVSThreadGraphConsumer.java
index 19c932085d..599af36b63 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TimeVSThreadGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TimeVSThreadGraphConsumer.java
@@ -36,23 +36,11 @@ import org.apache.jmeter.report.processor.graph.NameSeriesSelector;
  */
 public class TimeVSThreadGraphConsumer extends AbstractGraphConsumer {
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createKeysSelector()
-     */
     @Override
     protected final GraphKeysSelector createKeysSelector() {
         return sample -> (double) sample.getAllThreads();
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         return Collections.singletonMap(
@@ -63,12 +51,6 @@ public class TimeVSThreadGraphConsumer extends AbstractGraphConsumer {
                         new ElapsedTimeValueSelector(false), false, true));
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.processor.graph.AbstractGraphConsumer#
-     * initializeExtraResults(org.apache.jmeter.report.processor.MapResultData)
-     */
     @Override
     protected void initializeExtraResults(MapResultData parentResult) {
         // do nothing
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TotalTPSGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TotalTPSGraphConsumer.java
index 05f08e35b1..57a670dbb0 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TotalTPSGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TotalTPSGraphConsumer.java
@@ -46,13 +46,6 @@ public class TotalTPSGraphConsumer extends AbstractOverTimeGraphConsumer {
     private static final String TRANSACTION_SUCCESS_LABEL = String.format(STATUS_SERIES_FORMAT, "Transaction", SUCCESS_SERIES_SUFFIX);
     private static final String TRANSACTION_FAILURE_LABEL = String.format(STATUS_SERIES_FORMAT, "Transaction", FAILURE_SERIES_SUFFIX);
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -60,12 +53,6 @@ public class TotalTPSGraphConsumer extends AbstractOverTimeGraphConsumer {
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         AbstractSeriesSelector seriesSelector = new AbstractSeriesSelector(true) {
diff --git a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TransactionsPerSecondGraphConsumer.java b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TransactionsPerSecondGraphConsumer.java
index 332cd4ec5b..7e3eb49f1a 100644
--- a/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TransactionsPerSecondGraphConsumer.java
+++ b/src/core/src/main/java/org/apache/jmeter/report/processor/graph/impl/TransactionsPerSecondGraphConsumer.java
@@ -41,13 +41,6 @@ public class TransactionsPerSecondGraphConsumer extends AbstractOverTimeGraphCon
     private static final String SUCCESS_SERIES_SUFFIX = "success";
     private static final String FAILURE_SERIES_SUFFIX = "failure";
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see
-     * org.apache.jmeter.report.csv.processor.impl.AbstractOverTimeGraphConsumer
-     * #createTimeStampKeysSelector()
-     */
     @Override
     protected TimeStampKeysSelector createTimeStampKeysSelector() {
         TimeStampKeysSelector keysSelector = new TimeStampKeysSelector();
@@ -55,12 +48,6 @@ public class TransactionsPerSecondGraphConsumer extends AbstractOverTimeGraphCon
         return keysSelector;
     }
 
-    /*
-     * (non-Javadoc)
-     *
-     * @see org.apache.jmeter.report.csv.processor.impl.AbstractGraphConsumer#
-     * createGroupInfos()
-     */
     @Override
     protected Map<String, GroupInfo> createGroupInfos() {
         AbstractSeriesSelector seriesSelector = new AbstractSeriesSelector(true) {
diff --git a/src/core/src/main/java/org/apache/jmeter/reporters/ResultCollector.java b/src/core/src/main/java/org/apache/jmeter/reporters/ResultCollector.java
index 25a90d49ea..9a6e66caea 100644
--- a/src/core/src/main/java/org/apache/jmeter/reporters/ResultCollector.java
+++ b/src/core/src/main/java/org/apache/jmeter/reporters/ResultCollector.java
@@ -414,7 +414,7 @@ public class ResultCollector extends AbstractListenerElement implements SampleLi
             // Write the EOL separately so we generate LF line ends on Unix and Windows
             writer.print("\n"); // $NON-NLS-1$
             String pi=saveConfig.getXmlPi();
-            if (pi.length() > 0) {
+            if (!pi.isEmpty()) {
                 writer.println(pi);
             }
             // Can't do it as a static initialisation, because SaveService
diff --git a/src/core/src/main/java/org/apache/jmeter/reporters/ResultSaver.java b/src/core/src/main/java/org/apache/jmeter/reporters/ResultSaver.java
index fb81c3cb43..dc1d34d5fa 100644
--- a/src/core/src/main/java/org/apache/jmeter/reporters/ResultSaver.java
+++ b/src/core/src/main/java/org/apache/jmeter/reporters/ResultSaver.java
@@ -188,7 +188,7 @@ public class ResultSaver extends AbstractTestElement implements NoThreadClone, S
         }
         s.setResultFileName(fileName);// Associate sample with file name
         String variable = getVariableName();
-        if (variable.length() > 0) {
+        if (!variable.isEmpty()) {
             if (num > 0) {
                 variable = variable + num;
             }
diff --git a/src/core/src/main/java/org/apache/jmeter/reporters/Summariser.java b/src/core/src/main/java/org/apache/jmeter/reporters/Summariser.java
index 6a3cf1674b..700e908766 100644
--- a/src/core/src/main/java/org/apache/jmeter/reporters/Summariser.java
+++ b/src/core/src/main/java/org/apache/jmeter/reporters/Summariser.java
@@ -85,7 +85,7 @@ public class Summariser extends AbstractTestElement
                     "summariser.ignore_transaction_controller_sample_result", //$NON-NLS-1$
                     true);
 
-    /*
+    /**
      * Ensure that a report is not skipped if we are slightly late in checking
      * the time.
      */
@@ -96,14 +96,14 @@ public class Summariser extends AbstractTestElement
      */
     private static final Object LOCK = new Object();
 
-    /*
+    /**
      * This map allows summarisers with the same name to contribute to the same totals.
      */
     private static final Map<String, Totals> ACCUMULATORS = new ConcurrentHashMap<>();
 
     private static int instanceCount; // number of active tests
 
-    /*
+    /**
      * Cached copy of Totals for this instance.
      * The variables do not need to be synchronised,
      * as they are not shared between threads
@@ -114,7 +114,7 @@ public class Summariser extends AbstractTestElement
     // Name of the accumulator. Set up by testStarted().
     private transient String myName;
 
-    /*
+    /**
      * Constructor is initially called once for each occurrence in the test plan.
      * For GUI, several more instances are created.
      * Then clear is called at start of test.
@@ -140,9 +140,8 @@ public class Summariser extends AbstractTestElement
         setName(name);
     }
 
-    /*
+    /**
      * Contains the items needed to collect stats for a summariser
-     *
      */
     private static class Totals {
 
@@ -182,11 +181,9 @@ public class Summariser extends AbstractTestElement
         SummariserRunningSample myTotal = null;
         boolean reportNow = false;
 
-        /*
-         * Have we reached the reporting boundary?
-         * Need to allow for a margin of error, otherwise can miss the slot.
-         * Also need to check we've not hit the window already
-         */
+        // Have we reached the reporting boundary?
+        // Need to allow for a margin of error, otherwise can miss the slot.
+        // Also need to check we've not hit the window already
 
         synchronized (myTotals) {
             if (s != null) {
diff --git a/src/core/src/main/java/org/apache/jmeter/samplers/AsynchSampleSender.java b/src/core/src/main/java/org/apache/jmeter/samplers/AsynchSampleSender.java
index bd1337150c..e856cc5075 100644
--- a/src/core/src/main/java/org/apache/jmeter/samplers/AsynchSampleSender.java
+++ b/src/core/src/main/java/org/apache/jmeter/samplers/AsynchSampleSender.java
@@ -147,7 +147,11 @@ public class AsynchSampleSender extends AbstractSampleSender implements Serializ
                     SampleEvent e = queue.take();
                     // try to process as many as possible
                     // The == comparison is not an error
-                    while (!(eof = e == FINAL_EVENT) && e != null) {
+                    while (e != null) {
+                        eof = e == FINAL_EVENT;
+                        if (eof) {
+                            break;
+                        }
                         l.add(e);
                         e = queue.poll(); // returns null if nothing on queue currently
                     }
diff --git a/src/core/src/main/java/org/apache/jmeter/samplers/DiskStoreSampleSender.java b/src/core/src/main/java/org/apache/jmeter/samplers/DiskStoreSampleSender.java
index eec4da6131..5ded67756c 100644
--- a/src/core/src/main/java/org/apache/jmeter/samplers/DiskStoreSampleSender.java
+++ b/src/core/src/main/java/org/apache/jmeter/samplers/DiskStoreSampleSender.java
@@ -90,9 +90,9 @@ public class DiskStoreSampleSender extends AbstractSampleSender implements Seria
                 ObjectInputStream ois = new ObjectInputStream(fis)){
             Object obj;
             while((obj = ois.readObject()) != null) {
-                if (obj instanceof SampleEvent) {
+                if (obj instanceof SampleEvent sampleEvent) {
                     try {
-                        listener.sampleOccurred((SampleEvent) obj);
+                        listener.sampleOccurred(sampleEvent);
                     } catch (RemoteException err) {
                         if (err.getCause() instanceof java.net.ConnectException){
                             throw new JMeterError("Could not return sample",err);
diff --git a/src/core/src/main/java/org/apache/jmeter/samplers/RemoteSampleListenerImpl.java b/src/core/src/main/java/org/apache/jmeter/samplers/RemoteSampleListenerImpl.java
index b6e5c25131..2f7a44dfba 100644
--- a/src/core/src/main/java/org/apache/jmeter/samplers/RemoteSampleListenerImpl.java
+++ b/src/core/src/main/java/org/apache/jmeter/samplers/RemoteSampleListenerImpl.java
@@ -41,13 +41,13 @@ public class RemoteSampleListenerImpl extends java.rmi.server.UnicastRemoteObjec
 
     public RemoteSampleListenerImpl(Object listener) throws RemoteException {
         super(DEFAULT_LOCAL_PORT, RmiUtils.createClientSocketFactory(),  RmiUtils.createServerSocketFactory());
-        if (listener instanceof TestStateListener) {
-            testListener = (TestStateListener) listener;
+        if (listener instanceof TestStateListener testStateListener) {
+            testListener = testStateListener;
         } else {
             testListener = null;
         }
-        if (listener instanceof SampleListener) {
-            sampleListener = (SampleListener) listener;
+        if (listener instanceof SampleListener sampleListener1) {
+            sampleListener = sampleListener1;
         } else {
             sampleListener = null;
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/samplers/SampleResult.java b/src/core/src/main/java/org/apache/jmeter/samplers/SampleResult.java
index 4f69f05105..4888d250fc 100644
--- a/src/core/src/main/java/org/apache/jmeter/samplers/SampleResult.java
+++ b/src/core/src/main/java/org/apache/jmeter/samplers/SampleResult.java
@@ -641,7 +641,7 @@ public class SampleResult implements Serializable, Cloneable, Searchable {
             return;
         }
         String tn = getThreadName();
-        if (tn.length()==0) {
+        if (tn.isEmpty()) {
             tn=Thread.currentThread().getName();
             this.setThreadName(tn);
         }
@@ -892,7 +892,7 @@ public class SampleResult implements Serializable, Cloneable, Searchable {
         }
     }
 
-    /*
+    /**
      * Determine if content-type is known to be binary, i.e. not displayable as text.
      *
      * @param ct content type
@@ -1137,7 +1137,7 @@ public class SampleResult implements Serializable, Cloneable, Searchable {
         return startTime;
     }
 
-    /*
+    /**
      * Helper methods N.B. setStartTime must be called before setEndTime
      *
      * setStartTime is used by HTTPSampleResult to clone the parent sampler and
diff --git a/src/core/src/main/java/org/apache/jmeter/save/CSVSaveService.java b/src/core/src/main/java/org/apache/jmeter/save/CSVSaveService.java
index 76907e81e7..5843ac98a7 100644
--- a/src/core/src/main/java/org/apache/jmeter/save/CSVSaveService.java
+++ b/src/core/src/main/java/org/apache/jmeter/save/CSVSaveService.java
@@ -177,7 +177,11 @@ public final class CSVSaveService {
             // CSV output files should never contain empty lines, so probably
             // not
             // If so, then need to check whether the reader is at EOF
-            while ((parts = csvReadFile(dataReader, delim)).length != 0) {
+            while (true) {
+                parts = csvReadFile(dataReader, delim);
+                if (parts.length == 0) {
+                    break;
+                }
                 lineNumber++;
                 SampleEvent event = CSVSaveService.makeResultFromDelimitedString(parts, saveConfig, lineNumber);
                 if (event != null) {
@@ -541,7 +545,7 @@ public final class CSVSaveService {
                 varCount++;
             } else {
                 Functor set = headerLabelMethods.get(label);
-                set.invoke(saveConfig, new Boolean[]{Boolean.TRUE});
+                set.invoke(saveConfig, new Boolean[]{true});
             }
         }
 
@@ -758,7 +762,7 @@ public final class CSVSaveService {
                 .getDelimiter());
     }
 
-    /*
+    /**
      * Class to handle generating the delimited string. - adds the delimiter
      * if not the first call - quotes any strings that require it
      */
@@ -1053,50 +1057,50 @@ public final class CSVSaveService {
         while (-1 != (ch = infile.read())) {
             push = false;
             switch (state) {
-            case INITIAL:
-                if (ch == QUOTING_CHAR) {
-                    state = ParserState.QUOTED;
-                } else if (isDelimOrEOL(delim, ch)) {
-                    push = true;
-                } else {
-                    baos.write(ch);
-                    state = ParserState.PLAIN;
+                case INITIAL -> {
+                    if (ch == QUOTING_CHAR) {
+                        state = ParserState.QUOTED;
+                    } else if (isDelimOrEOL(delim, ch)) {
+                        push = true;
+                    } else {
+                        baos.write(ch);
+                        state = ParserState.PLAIN;
+                    }
                 }
-                break;
-            case PLAIN:
-                if (ch == QUOTING_CHAR) {
-                    baos.write(ch);
-                    throw new IOException(
-                            "Cannot have quote-char in plain field:["
-                                    + baos.toString() + "]");
-                } else if (isDelimOrEOL(delim, ch)) {
-                    push = true;
-                    state = ParserState.INITIAL;
-                } else {
-                    baos.write(ch);
+                case PLAIN -> {
+                    if (ch == QUOTING_CHAR) {
+                        baos.write(ch);
+                        throw new IOException(
+                                "Cannot have quote-char in plain field:["
+                                        + baos.toString() + "]");
+                    } else if (isDelimOrEOL(delim, ch)) {
+                        push = true;
+                        state = ParserState.INITIAL;
+                    } else {
+                        baos.write(ch);
+                    }
                 }
-                break;
-            case QUOTED:
-                if (ch == QUOTING_CHAR) {
-                    state = ParserState.EMBEDDEDQUOTE;
-                } else {
-                    baos.write(ch);
+                case QUOTED -> {
+                    if (ch == QUOTING_CHAR) {
+                        state = ParserState.EMBEDDEDQUOTE;
+                    } else {
+                        baos.write(ch);
+                    }
                 }
-                break;
-            case EMBEDDEDQUOTE:
-                if (ch == QUOTING_CHAR) {
-                    baos.write(QUOTING_CHAR); // doubled quote => quote
-                    state = ParserState.QUOTED;
-                } else if (isDelimOrEOL(delim, ch)) {
-                    push = true;
-                    state = ParserState.INITIAL;
-                } else {
-                    baos.write(QUOTING_CHAR);
-                    throw new IOException(
-                            "Cannot have single quote-char in quoted field:["
-                                    + baos.toString() + "]");
+                case EMBEDDEDQUOTE -> {
+                    if (ch == QUOTING_CHAR) {
+                        baos.write(QUOTING_CHAR); // doubled quote => quote
+                        state = ParserState.QUOTED;
+                    } else if (isDelimOrEOL(delim, ch)) {
+                        push = true;
+                        state = ParserState.INITIAL;
+                    } else {
+                        baos.write(QUOTING_CHAR);
+                        throw new IOException(
+                                "Cannot have single quote-char in quoted field:["
+                                        + baos.toString() + "]");
+                    }
                 }
-                break;
             } // switch(state)
             if (push) {
                 if (ch == '\r') {// Remove following \n if present
diff --git a/src/core/src/main/java/org/apache/jmeter/save/SaveService.java b/src/core/src/main/java/org/apache/jmeter/save/SaveService.java
index 6aba447dfb..5a41d6ea0f 100644
--- a/src/core/src/main/java/org/apache/jmeter/save/SaveService.java
+++ b/src/core/src/main/java/org/apache/jmeter/save/SaveService.java
@@ -180,7 +180,7 @@ public class SaveService {
 
     private static File getSaveServiceFile() {
         String saveServiceProps = JMeterUtils.getPropDefault(SAVESERVICE_PROPERTIES,SAVESERVICE_PROPERTIES_FILE); //$NON-NLS-1$
-        if (saveServiceProps.length() > 0){ //$NON-NLS-1$
+        if (!saveServiceProps.isEmpty()){ //$NON-NLS-1$
             return JMeterUtils.findFile(saveServiceProps);
         }
         throw new IllegalStateException("Could not find file configured in saveservice_properties property set to:"+saveServiceProps);
diff --git a/src/core/src/main/java/org/apache/jmeter/save/converters/ConversionHelp.java b/src/core/src/main/java/org/apache/jmeter/save/converters/ConversionHelp.java
index ee3750edde..445c0bafcd 100644
--- a/src/core/src/main/java/org/apache/jmeter/save/converters/ConversionHelp.java
+++ b/src/core/src/main/java/org/apache/jmeter/save/converters/ConversionHelp.java
@@ -56,7 +56,7 @@ public class ConversionHelp {
     private static final String ATT_TE_NAME      = "testname"; //$NON-NLS-1$
 
 
-    /*
+    /**
      * These must be set before reading/writing the XML. Rather a hack, but
      * saves changing all the method calls to include an extra variable.
      *
@@ -155,7 +155,7 @@ public class ConversionHelp {
 
     private static void saveClass(TestElement el, HierarchicalStreamWriter writer, String prop){
         String clazz=el.getPropertyAsString(prop);
-        if (clazz.length()>0) {
+        if (!clazz.isEmpty()) {
             writer.addAttribute(propertyToAttribute.get(prop),SaveService.classToAlias(clazz));
         }
     }
@@ -175,7 +175,7 @@ public class ConversionHelp {
     private static void saveItem(TestElement el, HierarchicalStreamWriter writer, String prop,
             boolean encode){
         String item=el.getPropertyAsString(prop);
-        if (item.length() > 0) {
+        if (!item.isEmpty()) {
             if (encode) {
                 item=ConversionHelp.encode(item);
             }
@@ -250,7 +250,7 @@ public class ConversionHelp {
         String testClass = (String) context.get(SaveService.TEST_CLASS_NAME);
         final String newName = NameUpdater.getCurrentName(name, testClass);
         // Delete any properties whose name converts to the empty string
-        if (name.length() != 0 && newName.length()==0) {
+        if (!name.isEmpty() && newName.isEmpty()) {
             return null;
         }
         return newName;
diff --git a/src/core/src/main/java/org/apache/jmeter/save/converters/SampleResultConverter.java b/src/core/src/main/java/org/apache/jmeter/save/converters/SampleResultConverter.java
index 857bb3f959..cbbc3887b4 100644
--- a/src/core/src/main/java/org/apache/jmeter/save/converters/SampleResultConverter.java
+++ b/src/core/src/main/java/org/apache/jmeter/save/converters/SampleResultConverter.java
@@ -375,7 +375,7 @@ public class SampleResultConverter extends AbstractCollectionConverter {
 
         // If we have a file, but no data, then read the file
         String resultFileName = res.getResultFileName();
-        if (resultFileName.length()>0
+        if (!resultFileName.isEmpty()
         &&  res.getResponseData().length == 0) {
             readFile(resultFileName,res);
         }
@@ -393,17 +393,17 @@ public class SampleResultConverter extends AbstractCollectionConverter {
     protected boolean retrieveItem(HierarchicalStreamReader reader, UnmarshallingContext context, SampleResult res,
             Object subItem) {
         String nodeName = reader.getNodeName();
-        if (subItem instanceof AssertionResult) {
-            res.addAssertionResult((AssertionResult) subItem);
-        } else if (subItem instanceof SampleResult) {
-            res.storeSubResult((SampleResult) subItem, false);
+        if (subItem instanceof AssertionResult assertionResult) {
+            res.addAssertionResult(assertionResult);
+        } else if (subItem instanceof SampleResult sampleResult) {
+            res.storeSubResult(sampleResult, false);
         } else if (nodeName.equals(TAG_RESPONSE_HEADER)) {
             res.setResponseHeaders((String) subItem);
         } else if (nodeName.equals(TAG_REQUEST_HEADER)) {
             res.setRequestHeaders((String) subItem);
         } else if (nodeName.equals(TAG_RESPONSE_DATA)) {
             final String responseData = (String) subItem;
-            if (responseData.length() > 0) {
+            if (!responseData.isEmpty()) {
                 final String dataEncoding = res.getDataEncodingWithDefault();
                 try {
                     res.setResponseData(responseData.getBytes(dataEncoding));
diff --git a/src/core/src/main/java/org/apache/jmeter/save/converters/TestElementConverter.java b/src/core/src/main/java/org/apache/jmeter/save/converters/TestElementConverter.java
index e7e521164d..efd617f22d 100644
--- a/src/core/src/main/java/org/apache/jmeter/save/converters/TestElementConverter.java
+++ b/src/core/src/main/java/org/apache/jmeter/save/converters/TestElementConverter.java
@@ -66,7 +66,7 @@ public class TestElementConverter extends AbstractCollectionConverter {
                 // Don't save empty comments - except for the TestPlan (to maintain compatibility)
                    if (!(
                            TestElement.COMMENTS.equals(jmp.getName())
-                           && jmp.getStringValue().length()==0
+                           && jmp.getStringValue().isEmpty()
                            && !el.getClass().equals(TestPlan.class)
                        ))
                    {
diff --git a/src/core/src/main/java/org/apache/jmeter/swing/HtmlPane.java b/src/core/src/main/java/org/apache/jmeter/swing/HtmlPane.java
index 1398aa4a65..8640eda839 100644
--- a/src/core/src/main/java/org/apache/jmeter/swing/HtmlPane.java
+++ b/src/core/src/main/java/org/apache/jmeter/swing/HtmlPane.java
@@ -41,7 +41,7 @@ public class HtmlPane extends JTextPane {
             String ref = e.getURL().getRef();
             if (ref != null) {
                 log.debug("reference to scroll to = '{}'", ref);
-                if (ref.length() > 0) {
+                if (!ref.isEmpty()) {
                     scrollToReference(ref);
                 } else { // href="#"
                     scrollRectToVisible(new Rectangle(1,1,1,1));
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/BooleanPropertyEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/BooleanPropertyEditor.java
index 8920f1fffc..132d90002d 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/BooleanPropertyEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/BooleanPropertyEditor.java
@@ -25,7 +25,7 @@ import java.beans.PropertyEditorSupport;
 public class BooleanPropertyEditor extends PropertyEditorSupport {
 
     // These are the mixed-case values as returned by the RI JVM boolean property editor
-    // However, they are different from the lower-case values returned by e.g. Boolean.FALSE.toString()
+    // However, they are different from the lower-case values returned by e.g. false.toString()
     private static final String FALSE = "False"; // $NON-NLS-1$
     private static final String TRUE  = "True";  // $NON-NLS-1$
 
@@ -35,7 +35,7 @@ public class BooleanPropertyEditor extends PropertyEditorSupport {
     @Override
     public String getAsText() {
         Object value = getValue();
-        return value instanceof Boolean ?  toString((Boolean) value) : null;
+        return value instanceof Boolean aBoolean ?  toString(aBoolean) : null;
     }
 
     private static String toString(Boolean value) {
@@ -49,8 +49,8 @@ public class BooleanPropertyEditor extends PropertyEditorSupport {
 
     @Override
     public void setValue(Object value){
-        if (value instanceof String) {
-            super.setValue(Boolean.valueOf((String) value));
+        if (value instanceof String string) {
+            super.setValue(Boolean.valueOf(string));
         } else if (value == null || value instanceof Boolean) {
             super.setValue(value); // not sure if null is passed in but no harm in setting it
         } else {
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/ComboStringEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/ComboStringEditor.java
index 4bf70be892..11a2eb2ca3 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/ComboStringEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/ComboStringEditor.java
@@ -65,7 +65,7 @@ class ComboStringEditor extends PropertyEditorSupport implements ItemListener, C
 
     private final DefaultComboBoxModel<Object> model;
 
-    /*
+    /**
      * Map of translations for tags; only created if there is at least
      * one tag and a ResourceBundle has been provided.
      */
@@ -293,8 +293,8 @@ class ComboStringEditor extends PropertyEditorSupport implements ItemListener, C
             if (this == other) {
                 return true;
             }
-            if (other instanceof UniqueObject) {
-                return propKey.equals(((UniqueObject) other).propKey);
+            if (other instanceof UniqueObject uniqueObject) {
+                return propKey.equals(uniqueObject.propKey);
             }
             return false;
         }
@@ -310,7 +310,7 @@ class ComboStringEditor extends PropertyEditorSupport implements ItemListener, C
         setAsText(initialEditValue);
     }
 
-    // Replace a string with its translation, if one exists
+    // Replace a string with its translation if one exists
     private String translate(String input) {
         if (validTranslations != null) {
             final String entry = validTranslations.get(input);
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/EnumEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/EnumEditor.java
index d16890a4ee..62e1f79f50 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/EnumEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/EnumEditor.java
@@ -51,8 +51,8 @@ class EnumEditor extends PropertyEditorSupport implements ClearGui {
             model.addElement((String) rb.getObject(e.toString()));
         }
         Object def = descriptor.getValue(GenericTestBeanCustomizer.DEFAULT);
-        if (def instanceof Integer) {
-            defaultIndex = (Integer) def;
+        if (def instanceof Integer integer) {
+            defaultIndex = integer;
         } else {
             defaultIndex = 0;
         }
@@ -81,11 +81,12 @@ class EnumEditor extends PropertyEditorSupport implements ClearGui {
     }
 
     @Override
+    @SuppressWarnings("EnumOrdinal")
     public void setValue(Object value) {
-        if (value instanceof Enum<?>){
-            combo.setSelectedIndex(((Enum<?>) value).ordinal());
-        } else if (value instanceof Integer) {
-            combo.setSelectedIndex((Integer) value);
+        if (value instanceof Enum<?> anEnum){
+            combo.setSelectedIndex(anEnum.ordinal());
+        } else if (value instanceof Integer integer) {
+            combo.setSelectedIndex(integer);
         } else {
             combo.setSelectedItem(value);
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/FieldStringEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/FieldStringEditor.java
index 7c329a93b3..d0988fbdc5 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/FieldStringEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/FieldStringEditor.java
@@ -77,8 +77,8 @@ class FieldStringEditor extends PropertyEditorSupport implements ActionListener,
 
     @Override
     public void setValue(Object value) {
-        if (value instanceof String) {
-            setAsText((String) value);
+        if (value instanceof String string) {
+            setAsText(string);
         } else if (value == null) {
             setAsText(null);
         } else {
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/GenericTestBeanCustomizer.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/GenericTestBeanCustomizer.java
index e053e9d209..b246102104 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/GenericTestBeanCustomizer.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/GenericTestBeanCustomizer.java
@@ -231,9 +231,9 @@ public class GenericTestBeanCustomizer extends JPanel implements SharedCustomize
 
             PropertyEditor propertyEditor;
             Object guiType = descriptor.getValue(GUITYPE);
-            if (guiType instanceof TypeEditor) {
-                propertyEditor = ((TypeEditor) guiType).getInstance(descriptor);
-            } else if (guiType instanceof Class && Enum.class.isAssignableFrom((Class<?>) guiType)) {
+            if (guiType instanceof TypeEditor typeEditor) {
+                propertyEditor = typeEditor.getInstance(descriptor);
+            } else if (guiType instanceof Class<?> aClass && Enum.class.isAssignableFrom(aClass)) {
                     @SuppressWarnings("unchecked") // we check the class type above
                     final Class<? extends Enum<?>> enumClass = (Class<? extends Enum<?>>) guiType;
                     propertyEditor = new EnumEditor(descriptor, enumClass, (ResourceBundle) descriptor.getValue(GenericTestBeanCustomizer.RESOURCE_BUNDLE));
@@ -271,9 +271,9 @@ public class GenericTestBeanCustomizer extends JPanel implements SharedCustomize
                 propertyEditor = createWrapperEditor(propertyEditor, descriptor);
                 log.debug("Editor for property {} is wrapped in {}", name, propertyEditor);
             }
-            if(propertyEditor instanceof TestBeanPropertyEditor)
+            if(propertyEditor instanceof TestBeanPropertyEditor testBeanPropertyEditor)
             {
-                ((TestBeanPropertyEditor)propertyEditor).setDescriptor(descriptor);
+                testBeanPropertyEditor.setDescriptor(descriptor);
             }
 
             if (propertyEditor instanceof TextAreaEditor) {
@@ -458,7 +458,7 @@ public class GenericTestBeanCustomizer extends JPanel implements SharedCustomize
      * Returns true if the property disallows constant values different from the provided tags.
      *
      * @param descriptor the property descriptor
-     * @return true if the attribute {@link #NOT_OTHER} is defined and equal to Boolean.TRUE;
+     * @return true if the attribute {@link #NOT_OTHER} is defined and equal to true;
      *  otherwise the default is false
      */
     static boolean notOther(PropertyDescriptor descriptor) {
@@ -469,7 +469,7 @@ public class GenericTestBeanCustomizer extends JPanel implements SharedCustomize
      * Returns true if the property does not allow JMeter expressions.
      *
      * @param descriptor the property descriptor
-     * @return true if the attribute {@link #NOT_EXPRESSION} is defined and equal to Boolean.TRUE;
+     * @return true if the attribute {@link #NOT_EXPRESSION} is defined and equal to true;
      *  otherwise the default is false
      */
     static boolean notExpression(PropertyDescriptor descriptor) {
@@ -480,7 +480,7 @@ public class GenericTestBeanCustomizer extends JPanel implements SharedCustomize
      * Returns true if the property must be defined (i.e. is required);
      *
      * @param descriptor the property descriptor
-     * @return true if the attribute {@link #NOT_UNDEFINED} is defined and equal to Boolean.TRUE;
+     * @return true if the attribute {@link #NOT_UNDEFINED} is defined and equal to true;
      *  otherwise the default is false
      */
     static boolean notNull(PropertyDescriptor descriptor) {
@@ -491,7 +491,7 @@ public class GenericTestBeanCustomizer extends JPanel implements SharedCustomize
      * Returns true if the property default value is not saved
      *
      * @param descriptor the property descriptor
-     * @return true if the attribute {@link #DEFAULT_NOT_SAVED} is defined and equal to Boolean.TRUE;
+     * @return true if the attribute {@link #DEFAULT_NOT_SAVED} is defined and equal to true;
      *  otherwise the default is false
      */
     static boolean noSaveDefault(PropertyDescriptor descriptor) {
@@ -704,7 +704,7 @@ public class GenericTestBeanCustomizer extends JPanel implements SharedCustomize
         private static final long serialVersionUID = 240L;
 
         private final BeanInfo beanInfo;
-        public PropertyComparator(BeanInfo beanInfo) {
+        private PropertyComparator(BeanInfo beanInfo) {
             this.beanInfo = beanInfo;
         }
 
@@ -790,10 +790,9 @@ public class GenericTestBeanCustomizer extends JPanel implements SharedCustomize
             PropertyEditor propertyEditor=editors[i]; // might be null (e.g. in testing)
             if (propertyEditor != null) {
                 try {
-                if (propertyEditor instanceof ClearGui) {
-                    ((ClearGui) propertyEditor).clearGui();
-                } else if (propertyEditor instanceof WrapperEditor){
-                    WrapperEditor we = (WrapperEditor) propertyEditor;
+                if (propertyEditor instanceof ClearGui clearGui) {
+                    clearGui.clearGui();
+                } else if (propertyEditor instanceof WrapperEditor we){
                     String[] tags = we.getTags();
                     if (tags != null && tags.length > 0) {
                         we.setAsText(tags[0]);
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/IntegerPropertyEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/IntegerPropertyEditor.java
index f4a521ef98..8468357cc5 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/IntegerPropertyEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/IntegerPropertyEditor.java
@@ -32,8 +32,8 @@ public class IntegerPropertyEditor extends PropertyEditorSupport {
 
     @Override
     public void setValue(Object value){
-        if (value instanceof String) {
-            super.setValue(Integer.decode((String) value)); // handles hex as well
+        if (value instanceof String string) {
+            super.setValue(Integer.decode(string)); // handles hex as well
         } else if (value == null || value instanceof Integer) {
             super.setValue(value); // not sure if null is passed in but no harm in setting it
         } else {
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/LongPropertyEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/LongPropertyEditor.java
index 1bb551826d..e590327591 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/LongPropertyEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/LongPropertyEditor.java
@@ -32,8 +32,8 @@ public class LongPropertyEditor extends PropertyEditorSupport {
 
     @Override
     public void setValue(Object value){
-        if (value instanceof String) {
-            super.setValue(Long.decode((String) value)); // handles hex as well
+        if (value instanceof String string) {
+            super.setValue(Long.decode(string)); // handles hex as well
         } else if (value == null || value instanceof Long) {
             super.setValue(value); // not sure if null is passed in but no harm in setting it
         } else {
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/PasswordEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/PasswordEditor.java
index 7d2a15f4ef..a5b3d98e55 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/PasswordEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/PasswordEditor.java
@@ -70,8 +70,8 @@ public class PasswordEditor extends PropertyEditorSupport implements ActionListe
 
     @Override
     public void setValue(Object value) {
-        if (value instanceof String) {
-            setAsText((String) value);
+        if (value instanceof String string) {
+            setAsText(string);
         } else {
             throw new IllegalArgumentException();
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TableEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TableEditor.java
index f5a5998120..83b3abd2be 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TableEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TableEditor.java
@@ -179,8 +179,8 @@ public class TableEditor extends PropertyEditorSupport implements FocusListener,
     private static Collection<Object> convertCollection(Collection<?> values) {
         List<Object> l = new ArrayList<>();
         for(Object obj : values) {
-            if(obj instanceof TestElementProperty) {
-                l.add(((TestElementProperty)obj).getElement());
+            if (obj instanceof TestElementProperty testElementProperty) {
+                l.add(testElementProperty.getElement());
             } else {
                 l.add(obj);
             }
@@ -215,23 +215,23 @@ public class TableEditor extends PropertyEditorSupport implements FocusListener,
     void initializeModel()
     {
         Object hdrs = descriptor.getValue(HEADERS);
-        if (!(hdrs instanceof String[])) {
+        if (!(hdrs instanceof String[] headers)) {
             throw new RuntimeException("attribute HEADERS must be a String array");
         }
         if (clazz == String.class) {
-            model = new ObjectTableModel((String[]) hdrs, new Functor[0], new Functor[0], new Class[]{String.class});
+            model = new ObjectTableModel(headers, new Functor[0], new Functor[0], new Class[]{String.class});
         } else {
             Object value = descriptor.getValue(OBJECT_PROPERTIES);
-            if (!(value instanceof String[])) {
+            if (!(value instanceof String[] valueArray)) {
                 throw new RuntimeException("attribute OBJECT_PROPERTIES must be a String array");
             }
-            List<String> props = Arrays.stream((String[]) value)
+            List<String> props = Arrays.stream(valueArray)
                     .map(StringUtilities::capitalize)
                     .collect(Collectors.toList());
             Functor[] writers = createWriters(props);
             Functor[] readers = createReaders(clazz, props);
             Class<?>[] editors = getArgsForWriter(clazz, props);
-            model = new ObjectTableModel((String[]) hdrs, readers, writers, editors);
+            model = new ObjectTableModel(headers, readers, writers, editors);
         }
         model.addTableModelListener(this);
         table = new JTable(model);
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TestBeanGUI.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TestBeanGUI.java
index a9ba4405e4..82285b60ea 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TestBeanGUI.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TestBeanGUI.java
@@ -230,8 +230,7 @@ public class TestBeanGUI extends AbstractJMeterGuiComponent implements JMeterGUI
     @Override
     public void modifyTestElement(TestElement element) {
         // Fetch data from screen fields
-        if (customizer instanceof GenericTestBeanCustomizer) {
-            GenericTestBeanCustomizer gtbc = (GenericTestBeanCustomizer) customizer;
+        if (customizer instanceof GenericTestBeanCustomizer gtbc) {
             gtbc.saveGuiFields();
         }
         configureTestElement(element);
@@ -454,8 +453,7 @@ public class TestBeanGUI extends AbstractJMeterGuiComponent implements JMeterGUI
     @Override
     public void clearGui() {
         super.clearGui();
-        if (customizer instanceof GenericTestBeanCustomizer) {
-            GenericTestBeanCustomizer gtbc = (GenericTestBeanCustomizer) customizer;
+        if (customizer instanceof GenericTestBeanCustomizer gtbc) {
             gtbc.clearGuiFields();
         }
         propertyMap.clear();
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TextAreaEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TextAreaEditor.java
index 76d2e9b2f4..c6726ca1f5 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TextAreaEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/TextAreaEditor.java
@@ -132,8 +132,7 @@ public class TextAreaEditor extends PropertyEditorSupport implements FocusListen
     @Override
     public void propertyChange(PropertyChangeEvent evt) {
         Object source = evt.getSource();
-        if (source instanceof ComboStringEditor) {
-            ComboStringEditor cse = (ComboStringEditor) source;
+        if (source instanceof ComboStringEditor cse) {
             String lang = cse.getAsText().toLowerCase(Locale.ROOT);
             textUI.setLanguage(lang);
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/WrapperEditor.java b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/WrapperEditor.java
index 754979be12..64fac96136 100644
--- a/src/core/src/main/java/org/apache/jmeter/testbeans/gui/WrapperEditor.java
+++ b/src/core/src/main/java/org/apache/jmeter/testbeans/gui/WrapperEditor.java
@@ -120,7 +120,7 @@ class WrapperEditor extends PropertyEditorSupport implements PropertyChangeListe
 
         resetValue();
 
-        if (guiEditor instanceof ComboStringEditor) {
+        if (guiEditor instanceof ComboStringEditor comboStringEditor) {
             String[] tags = guiEditor.getTags();
 
             // Provide an initial edit value if necessary -- this is a heuristic
@@ -139,7 +139,7 @@ class WrapperEditor extends PropertyEditorSupport implements PropertyChangeListe
                 v = getAsText();
             }
 
-            ((ComboStringEditor) guiEditor).setInitialEditValue(v);
+            comboStringEditor.setInitialEditValue(v);
         }
 
         guiEditor.addPropertyChangeListener(this);
@@ -260,7 +260,7 @@ class WrapperEditor extends PropertyEditorSupport implements PropertyChangeListe
      * @return true if text is a String and isExpression(text).
      */
     private static boolean isExpression(Object text) {
-        return text instanceof String && isExpression((String) text);
+        return text instanceof String str && isExpression(str);
     }
 
     /**
@@ -294,7 +294,7 @@ class WrapperEditor extends PropertyEditorSupport implements PropertyChangeListe
                     try {
                         typeEditor.setAsText(text);
                     } catch (NumberFormatException e) {
-                        if (text.length() == 0){
+                        if (text.isEmpty()){
                             text = "0";//$NON-NLS-1$
                             typeEditor.setAsText(text);
                         } else {
@@ -350,7 +350,7 @@ class WrapperEditor extends PropertyEditorSupport implements PropertyChangeListe
         guiEditor.setValue(text);
     }
 
-    /*
+    /**
      * Fix bug in JVMs that return true/false rather than True/False
      * from the type editor getAsText() method
      */
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/AbstractTestElement.java b/src/core/src/main/java/org/apache/jmeter/testelement/AbstractTestElement.java
index 920cdfbb11..84527726b7 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/AbstractTestElement.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/AbstractTestElement.java
@@ -340,10 +340,10 @@ public abstract class AbstractTestElement implements TestElement, Serializable,
         traverser.startProperty(value);
         if (value instanceof TestElementProperty) {
             ((TestElement) value.getObjectValue()).traverse(traverser);
-        } else if (value instanceof CollectionProperty) {
-            traverseCollection((CollectionProperty) value, traverser);
-        } else if (value instanceof MapProperty) {
-            traverseMap((MapProperty) value, traverser);
+        } else if (value instanceof CollectionProperty collectionProperty) {
+            traverseCollection(collectionProperty, traverser);
+        } else if (value instanceof MapProperty mapProperty) {
+            traverseMap(mapProperty, traverser);
         }
         traverser.endProperty(value);
     }
@@ -742,10 +742,8 @@ public abstract class AbstractTestElement implements TestElement, Serializable,
     @Override
     public JMeterContext getThreadContext() {
         if (threadContext == null) {
-            /*
-             * Only samplers have the thread context set up by JMeterThread at
-             * present, so suppress the warning for now
-             */
+            // Only samplers have the thread context set up by JMeterThread at
+            // present, so suppress the warning for now
             threadContext = JMeterContextService.getContext();
         }
         return threadContext;
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/TestPlan.java b/src/core/src/main/java/org/apache/jmeter/testelement/TestPlan.java
index 4f9058ef5f..a2efd88b11 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/TestPlan.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/TestPlan.java
@@ -197,8 +197,8 @@ public class TestPlan extends AbstractTestElement implements Serializable, TestS
     @Override
     public void addTestElement(TestElement tg) {
         super.addTestElement(tg);
-        if (tg instanceof AbstractThreadGroup && !isRunningVersion()) {
-            addThreadGroup((AbstractThreadGroup) tg);
+        if (tg instanceof AbstractThreadGroup abstractThreadGroup && !isRunningVersion()) {
+            addThreadGroup(abstractThreadGroup);
         }
     }
 
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/property/BooleanProperty.java b/src/core/src/main/java/org/apache/jmeter/testelement/property/BooleanProperty.java
index ea6c5797bb..9d13240210 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/property/BooleanProperty.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/property/BooleanProperty.java
@@ -39,8 +39,8 @@ public class BooleanProperty extends AbstractProperty {
 
     @Override
     public void setObjectValue(Object v) {
-        if (v instanceof Boolean) {
-            value = (Boolean) v;
+        if (v instanceof Boolean b) {
+            value = b;
         } else {
             value = Boolean.parseBoolean(v.toString());
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/property/CollectionProperty.java b/src/core/src/main/java/org/apache/jmeter/testelement/property/CollectionProperty.java
index 09d89c9364..752c98ed25 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/property/CollectionProperty.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/property/CollectionProperty.java
@@ -95,8 +95,8 @@ public class CollectionProperty extends MultiProperty {
      */
     @Override
     public void setObjectValue(Object v) {
-        if (v instanceof Collection<?>) {
-            setCollection((Collection<?>) v);
+        if (v instanceof Collection<?> objects) {
+            setCollection(objects);
         }
 
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/property/FunctionProperty.java b/src/core/src/main/java/org/apache/jmeter/testelement/property/FunctionProperty.java
index 238ec0184f..68853ccff4 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/property/FunctionProperty.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/property/FunctionProperty.java
@@ -54,8 +54,8 @@ public class FunctionProperty extends AbstractProperty {
 
     @Override
     public void setObjectValue(Object v) {
-        if (v instanceof CompoundVariable && !isRunningVersion()) {
-            function = (CompoundVariable) v;
+        if (v instanceof CompoundVariable compoundVariable && !isRunningVersion()) {
+            function = compoundVariable;
         } else {
             overrideValue = v.toString();
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/property/MapProperty.java b/src/core/src/main/java/org/apache/jmeter/testelement/property/MapProperty.java
index ee73eb3adb..0af7480ce8 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/property/MapProperty.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/property/MapProperty.java
@@ -65,8 +65,8 @@ public class MapProperty extends MultiProperty {
     /** {@inheritDoc} */
     @Override
     public void setObjectValue(Object v) {
-        if (v instanceof Map<?, ?>) {
-            setMap((Map<?, ?>) v);
+        if (v instanceof Map<?, ?> map) {
+            setMap(map);
         }
     }
 
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/property/MultiProperty.java b/src/core/src/main/java/org/apache/jmeter/testelement/property/MultiProperty.java
index 3babeed20e..bfd1397a82 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/property/MultiProperty.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/property/MultiProperty.java
@@ -82,8 +82,8 @@ public abstract class MultiProperty extends AbstractProperty implements Iterable
             return;
         }
         log.debug("merging in {}", prop.getClass());
-        if (prop instanceof MultiProperty) {
-            for (JMeterProperty item : (MultiProperty) prop) {
+        if (prop instanceof MultiProperty multiProperty) {
+            for (JMeterProperty item : multiProperty) {
                 addProperty(item);
             }
         } else {
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/property/NumberProperty.java b/src/core/src/main/java/org/apache/jmeter/testelement/property/NumberProperty.java
index f2f4bac1de..ff53399f60 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/property/NumberProperty.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/property/NumberProperty.java
@@ -48,8 +48,8 @@ public abstract class NumberProperty extends AbstractProperty {
 
     @Override
     public void setObjectValue(Object v) {
-        if (v instanceof Number) {
-            setNumberValue((Number) v);
+        if (v instanceof Number number) {
+            setNumberValue(number);
         } else {
             try {
                 setNumberValue(v.toString());
diff --git a/src/core/src/main/java/org/apache/jmeter/testelement/property/TestElementProperty.java b/src/core/src/main/java/org/apache/jmeter/testelement/property/TestElementProperty.java
index d1231b1bf3..22fa0d62dc 100644
--- a/src/core/src/main/java/org/apache/jmeter/testelement/property/TestElementProperty.java
+++ b/src/core/src/main/java/org/apache/jmeter/testelement/property/TestElementProperty.java
@@ -72,8 +72,8 @@ public class TestElementProperty extends MultiProperty {
      */
     @Override
     public void setObjectValue(Object v) {
-        if (v instanceof TestElement) {
-            value = (TestElement) v;
+        if (v instanceof TestElement testElement) {
+            value = testElement;
         }
     }
 
diff --git a/src/core/src/main/java/org/apache/jmeter/threads/FindTestElementsUpToRootTraverser.java b/src/core/src/main/java/org/apache/jmeter/threads/FindTestElementsUpToRootTraverser.java
index 6613e1b02c..19ba1aea9c 100644
--- a/src/core/src/main/java/org/apache/jmeter/threads/FindTestElementsUpToRootTraverser.java
+++ b/src/core/src/main/java/org/apache/jmeter/threads/FindTestElementsUpToRootTraverser.java
@@ -93,8 +93,8 @@ public class FindTestElementsUpToRootTraverser implements HashTreeTraverser {
         Deque<TestElement> stackLocalCopy = new ArrayDeque<>(stack);
         while(!stackLocalCopy.isEmpty()) {
             TestElement te = stackLocalCopy.getLast();
-            if(te instanceof Controller) {
-                result.add((Controller)te);
+            if (te instanceof Controller controller) {
+                result.add(controller);
             }
             stackLocalCopy.removeLast();
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/threads/JMeterThread.java b/src/core/src/main/java/org/apache/jmeter/threads/JMeterThread.java
index 01a7458188..35f94b2698 100644
--- a/src/core/src/main/java/org/apache/jmeter/threads/JMeterThread.java
+++ b/src/core/src/main/java/org/apache/jmeter/threads/JMeterThread.java
@@ -282,17 +282,14 @@ public class JMeterThread implements Runnable, Interruptible {
                             triggerLoopLogicalActionOnParentControllers(sam, threadContext, JMeterThread::continueOnThreadLoop);
                         } else {
                             switch (threadContext.getTestLogicalAction()) {
-                                case BREAK_CURRENT_LOOP:
-                                    triggerLoopLogicalActionOnParentControllers(sam, threadContext, JMeterThread::breakOnCurrentLoop);
-                                    break;
-                                case START_NEXT_ITERATION_OF_THREAD:
-                                    triggerLoopLogicalActionOnParentControllers(sam, threadContext, JMeterThread::continueOnThreadLoop);
-                                    break;
-                                case START_NEXT_ITERATION_OF_CURRENT_LOOP:
-                                    triggerLoopLogicalActionOnParentControllers(sam, threadContext, JMeterThread::continueOnCurrentLoop);
-                                    break;
-                                default:
-                                    break;
+                                case BREAK_CURRENT_LOOP ->
+                                        triggerLoopLogicalActionOnParentControllers(sam, threadContext, JMeterThread::breakOnCurrentLoop);
+                                case START_NEXT_ITERATION_OF_THREAD ->
+                                        triggerLoopLogicalActionOnParentControllers(sam, threadContext, JMeterThread::continueOnThreadLoop);
+                                case START_NEXT_ITERATION_OF_CURRENT_LOOP ->
+                                        triggerLoopLogicalActionOnParentControllers(sam, threadContext, JMeterThread::continueOnCurrentLoop);
+                                default -> {
+                                }
                             }
                         }
                         threadContext.setTestLogicalAction(TestLogicalAction.CONTINUE);
@@ -427,8 +424,7 @@ public class JMeterThread implements Runnable, Interruptible {
     private static void continueOnThreadLoop(FindTestElementsUpToRootTraverser pathToRootTraverser) {
         List<Controller> controllersToReinit = pathToRootTraverser.getControllersToRoot();
         for (Controller parentController : controllersToReinit) {
-            if (parentController instanceof AbstractThreadGroup) {
-                AbstractThreadGroup tg = (AbstractThreadGroup) parentController;
+            if (parentController instanceof AbstractThreadGroup tg) {
                 tg.startNextLoop();
             } else {
                 parentController.triggerEndOfLoop();
@@ -742,11 +738,9 @@ public class JMeterThread implements Runnable, Interruptible {
         if (log.isInfoEnabled()) {
             log.info("Thread started: {}", Thread.currentThread().getName());
         }
-        /*
-         * Setting SamplingStarted before the controllers are initialised allows
-         * them to access the running values of functions and variables (however
-         * it does not seem to help with the listeners)
-         */
+        // Setting SamplingStarted before the controllers are initialised allows
+        // them to access the running values of functions and variables (however
+        // it does not seem to help with the listeners)
         threadContext.setSamplingStarted(true);
 
         threadGroupLoopController.initialize();
@@ -840,12 +834,12 @@ public class JMeterThread implements Runnable, Interruptible {
         interruptLock.lock();
         try {
             Sampler samp = currentSamplerForInterruption; // fetch once; must be done under lock
-            if (samp instanceof Interruptible){ // (also protects against null)
+            if (samp instanceof Interruptible interruptible){ // (also protects against null)
                 if (log.isWarnEnabled()) {
                     log.warn("Interrupting: {} sampler: {}", threadName, samp.getName());
                 }
                 try {
-                    boolean found = ((Interruptible)samp).interrupt();
+                    boolean found = interruptible.interrupt();
                     if (!found) {
                         log.warn("No operation pending");
                     }
diff --git a/src/core/src/main/java/org/apache/jmeter/threads/JMeterVariables.java b/src/core/src/main/java/org/apache/jmeter/threads/JMeterVariables.java
index 7f652380e7..c13f1878f7 100644
--- a/src/core/src/main/java/org/apache/jmeter/threads/JMeterVariables.java
+++ b/src/core/src/main/java/org/apache/jmeter/threads/JMeterVariables.java
@@ -136,8 +136,8 @@ public class JMeterVariables {
      */
     public String get(String key) {
         Object o = variables.get(key);
-        if(o instanceof String) {
-            return (String) o;
+        if (o instanceof String string) {
+            return string;
         } else if (o != null) {
             return o.toString();
         } else {
diff --git a/src/core/src/main/java/org/apache/jmeter/threads/RemoteThreadsListenerImpl.java b/src/core/src/main/java/org/apache/jmeter/threads/RemoteThreadsListenerImpl.java
index 058702827a..8d4d75ee59 100644
--- a/src/core/src/main/java/org/apache/jmeter/threads/RemoteThreadsListenerImpl.java
+++ b/src/core/src/main/java/org/apache/jmeter/threads/RemoteThreadsListenerImpl.java
@@ -86,9 +86,6 @@ public class RemoteThreadsListenerImpl extends UnicastRemoteObject implements
         }
     }
 
-    /* (non-Javadoc)
-     * @see org.apache.jmeter.samplers.RemoteThreadsListener#threadFinished()
-     */
     @Override
     public void threadFinished() {
         JMeterContextService.decrNumberOfThreads();
diff --git a/src/core/src/main/java/org/apache/jmeter/threads/TestCompiler.java b/src/core/src/main/java/org/apache/jmeter/threads/TestCompiler.java
index 626d3ce858..14b537a0e1 100644
--- a/src/core/src/main/java/org/apache/jmeter/threads/TestCompiler.java
+++ b/src/core/src/main/java/org/apache/jmeter/threads/TestCompiler.java
@@ -282,7 +282,7 @@ public class TestCompiler implements HashTreeTraverser {
         private final TestElement child;
         private final TestElement parent;
 
-        public ObjectPair(TestElement child, TestElement parent) {
+        private ObjectPair(TestElement child, TestElement parent) {
             this.child = child;
             this.parent = parent;
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/threads/ThreadGroup.java b/src/core/src/main/java/org/apache/jmeter/threads/ThreadGroup.java
index ac483d4bce..9599fe0e1c 100644
--- a/src/core/src/main/java/org/apache/jmeter/threads/ThreadGroup.java
+++ b/src/core/src/main/java/org/apache/jmeter/threads/ThreadGroup.java
@@ -522,7 +522,7 @@ public class ThreadGroup extends AbstractThreadGroup {
          * Pause ms milliseconds
          * @param ms long milliseconds
          */
-        private void pause(long ms){
+        private static void pause(long ms){
             try {
                 TimeUnit.MILLISECONDS.sleep(ms);
             } catch (InterruptedException e) {
diff --git a/src/core/src/main/java/org/apache/jmeter/threads/gui/ThreadGroupGui.java b/src/core/src/main/java/org/apache/jmeter/threads/gui/ThreadGroupGui.java
index 468381563f..3ddcd1f96e 100644
--- a/src/core/src/main/java/org/apache/jmeter/threads/gui/ThreadGroupGui.java
+++ b/src/core/src/main/java/org/apache/jmeter/threads/gui/ThreadGroupGui.java
@@ -124,8 +124,8 @@ public class ThreadGroupGui extends AbstractThreadGroupGui implements ItemListen
     @Override
     public void modifyTestElement(TestElement tg) {
         super.modifyTestElement(tg);
-        if (tg instanceof AbstractThreadGroup) {
-            ((AbstractThreadGroup) tg).setSamplerController((LoopController) loopPanel.createTestElement());
+        if (tg instanceof AbstractThreadGroup abstractThreadGroup) {
+            abstractThreadGroup.setSamplerController((LoopController) loopPanel.createTestElement());
         }
     }
 
diff --git a/src/core/src/main/java/org/apache/jmeter/timers/TimerService.java b/src/core/src/main/java/org/apache/jmeter/timers/TimerService.java
index b0cc752476..e20683e07b 100644
--- a/src/core/src/main/java/org/apache/jmeter/timers/TimerService.java
+++ b/src/core/src/main/java/org/apache/jmeter/timers/TimerService.java
@@ -34,7 +34,7 @@ public class TimerService {
      * Initialization On Demand Holder pattern
      */
     private static class TimerServiceHolder {
-        public static final TimerService INSTANCE = new TimerService();
+        private static final TimerService INSTANCE = new TimerService();
     }
 
     /**
diff --git a/src/core/src/main/java/org/apache/jmeter/util/BSFJavaScriptEngine.java b/src/core/src/main/java/org/apache/jmeter/util/BSFJavaScriptEngine.java
index e1712fc4f8..68704a40a0 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/BSFJavaScriptEngine.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/BSFJavaScriptEngine.java
@@ -86,8 +86,8 @@ public class BSFJavaScriptEngine extends BSFEngineImpl {
 
             retval =
                 ((Function) fun).call(cx, global, global, args);
-            if (retval instanceof Wrapper) {
-                retval = ((Wrapper) retval).unwrap();
+            if (retval instanceof Wrapper wrapper) {
+                retval = wrapper.unwrap();
             }
         }
         catch (Throwable t) { //NOSONAR We handle correctly Error case in function
@@ -139,8 +139,8 @@ public class BSFJavaScriptEngine extends BSFEngineImpl {
                                        source, lineNo,
                                        null);
 
-            if (retval instanceof NativeJavaObject) {
-                retval = ((NativeJavaObject) retval).unwrap();
+            if (retval instanceof NativeJavaObject nativeJavaObject) {
+                retval = nativeJavaObject.unwrap();
             }
 
         }
@@ -159,20 +159,20 @@ public class BSFJavaScriptEngine extends BSFEngineImpl {
      */
     private static void handleError(Throwable t) throws BSFException {
         Throwable target = t;
-        if (t instanceof WrappedException) {
-            target = ((WrappedException) t).getWrappedException();
+        if (t instanceof WrappedException wrappedException) {
+            target = wrappedException.getWrappedException();
         }
 
         String message = null;
-        if (target instanceof JavaScriptException) {
+        if (target instanceof JavaScriptException javaScriptException) {
             message = target.getLocalizedMessage();
 
             // Is it an exception wrapped in a JavaScriptException?
-            Object value = ((JavaScriptException) target).getValue();
-            if (value instanceof Throwable) {
+            Object value = javaScriptException.getValue();
+            if (value instanceof Throwable throwable) {
                 // likely a wrapped exception from a LiveConnect call.
                 // Display its stack trace as a diagnostic
-                target = (Throwable) value;
+                target = throwable;
             }
         }
         else if (target instanceof EvaluatorException ||
@@ -190,12 +190,12 @@ public class BSFJavaScriptEngine extends BSFEngineImpl {
             message = target.toString();
         }
 
-        if (target instanceof Error && !(target instanceof StackOverflowError)) {
+        if (target instanceof Error error && !(target instanceof StackOverflowError)) {
             // Re-throw Errors because we're supposed to let the JVM see it
             // Don't re-throw StackOverflows, because we know we've
             // corrected the situation by aborting the loop and
             // a long stacktrace would end up on the user's console
-            throw (Error) target;
+            throw error;
         }
         else {
             throw new BSFException(BSFException.REASON_OTHER_ERROR,
diff --git a/src/core/src/main/java/org/apache/jmeter/util/BSFTestElement.java b/src/core/src/main/java/org/apache/jmeter/util/BSFTestElement.java
index 8b3a49f3ea..6a2219ba07 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/BSFTestElement.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/BSFTestElement.java
@@ -94,7 +94,7 @@ public abstract class BSFTestElement extends ScriptingTestElement
     protected void processFileOrScript(BSFManager mgr) throws BSFException{
         BSFEngine bsfEngine = mgr.loadScriptingEngine(getScriptLanguage());
         final String scriptFile = getFilename();
-        if (scriptFile.length() == 0) {
+        if (scriptFile.isEmpty()) {
             bsfEngine.exec("[script]",0,0,getScript());
         } else {// we have a file, read and process it
             try {
@@ -112,7 +112,7 @@ public abstract class BSFTestElement extends ScriptingTestElement
     protected Object evalFileOrScript(BSFManager mgr) throws BSFException{
         BSFEngine bsfEngine = mgr.loadScriptingEngine(getScriptLanguage());
         final String scriptFile = getFilename();
-        if (scriptFile.length() == 0) {
+        if (scriptFile.isEmpty()) {
             return bsfEngine.eval("[script]",0,0,getScript());
         } else {// we have a file, read and process it
             try {
diff --git a/src/core/src/main/java/org/apache/jmeter/util/BeanShellBeanInfoSupport.java b/src/core/src/main/java/org/apache/jmeter/util/BeanShellBeanInfoSupport.java
index 86bd865faf..bb5aaccf53 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/BeanShellBeanInfoSupport.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/BeanShellBeanInfoSupport.java
@@ -34,28 +34,28 @@ public abstract class BeanShellBeanInfoSupport extends BeanInfoSupport {
         PropertyDescriptor p;
 
         p = property("resetInterpreter");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-        p.setValue(DEFAULT, Boolean.FALSE);
-        p.setValue(NOT_EXPRESSION, Boolean.TRUE);
-        p.setValue(NOT_OTHER, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
+        p.setValue(DEFAULT, false);
+        p.setValue(NOT_EXPRESSION, true);
+        p.setValue(NOT_OTHER, true);
 
         createPropertyGroup("resetGroup", new String[] { "resetInterpreter" });
 
         p = property("parameters");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "");
 
         createPropertyGroup("parameterGroup", new String[] { "parameters" });
 
         p = property("filename");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "");
         p.setPropertyEditorClass(FileEditor.class);
 
         createPropertyGroup("filenameGroup", new String[] { "filename" });
 
         p = property("script");
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, "");
         p.setPropertyEditorClass(TextAreaEditor.class);
 
diff --git a/src/core/src/main/java/org/apache/jmeter/util/BeanShellServer.java b/src/core/src/main/java/org/apache/jmeter/util/BeanShellServer.java
index a45081ac40..8d1344e340 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/BeanShellServer.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/BeanShellServer.java
@@ -84,7 +84,7 @@ public class BeanShellServer implements Runnable {
             setObj.invoke(instance, "t", this );//$NON-NLS-1$
             setInt.invoke(instance, "portnum", serverport);//$NON-NLS-1$
 
-            if (serverfile.length() > 0) {
+            if (!serverfile.isEmpty()) {
                 try {
                     source.invoke(instance, serverfile);
                 } catch (InvocationTargetException ite) {
@@ -93,8 +93,8 @@ public class BeanShellServer implements Runnable {
                         log.warn("Could not source, {}. {}", serverfile,
                                 (cause != null) ? cause.toString() : ite.toString());
                     }
-                    if (cause instanceof Error) {
-                        throw (Error) cause;
+                    if (cause instanceof Error error) {
+                        throw error;
                     }
                 }
             }
diff --git a/src/core/src/main/java/org/apache/jmeter/util/BeanShellTestElement.java b/src/core/src/main/java/org/apache/jmeter/util/BeanShellTestElement.java
index 88b9bdd1bc..f012f6cc30 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/BeanShellTestElement.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/BeanShellTestElement.java
@@ -158,7 +158,7 @@ public abstract class BeanShellTestElement extends AbstractTestElement
         bsh.set("bsh.args",//$NON-NLS-1$
                 JOrphanUtils.split(params, " "));//$NON-NLS-1$
 
-        if (fileName.length() == 0) {
+        if (fileName.isEmpty()) {
             String bshScript = getScript();
             if (sampleResult != null) {
                 sampleResult.setSamplerData(bshScript);
diff --git a/src/core/src/main/java/org/apache/jmeter/util/CustomX509TrustManager.java b/src/core/src/main/java/org/apache/jmeter/util/CustomX509TrustManager.java
index ca335f7f34..d2ff071198 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/CustomX509TrustManager.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/CustomX509TrustManager.java
@@ -57,12 +57,14 @@ public class CustomX509TrustManager implements X509TrustManager
             for (int i = 0; i < certificates.length; i++) {
                 X509Certificate cert = certificates[i];
                 log.debug(
-                        " Client certificate {}:\n"
-                        + "  Subject DN: {}\n"
-                        + "  Signature Algorithm: {}\n"
-                        + "  Valid from: {}\n"
-                        + "  Valid until: {}\n"
-                        + "  Issuer: {}",
+                        """
+                        Client certificate {}:
+                          Subject DN: {}
+                          Signature Algorithm: {}
+                          Valid from: {}
+                          Valid until: {}
+                          Issuer: {}\
+                        """,
                         i + 1,
                         cert.getSubjectX500Principal(),
                         cert.getSigAlgName(),
@@ -83,12 +85,14 @@ public class CustomX509TrustManager implements X509TrustManager
             for (int i = 0; i < certificates.length; i++) {
                 X509Certificate cert = certificates[i];
                 log.debug(
-                        " Server certificate {}:\n"
-                        + "  Subject DN: {}\n"
-                        + "  Signature Algorithm: {}\n"
-                        + "  Valid from: {}\n"
-                        + "  Valid until: {}\n"
-                        + "  Issuer: {}",
+                        """
+                        Server certificate {}:
+                          Subject DN: {}
+                          Signature Algorithm: {}
+                          Valid from: {}
+                          Valid until: {}
+                          Issuer: {}\
+                        """,
                         i + 1,
                         cert.getSubjectX500Principal(),
                         cert.getSigAlgName(),
diff --git a/src/core/src/main/java/org/apache/jmeter/util/Document.java b/src/core/src/main/java/org/apache/jmeter/util/Document.java
index e25bfd4cb1..7b0ca1059e 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/Document.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/Document.java
@@ -75,7 +75,7 @@ public class Document {
             }
         }
 
-        if (response.length() == 0 && document.length > 0) {
+        if (response.isEmpty() && document.length > 0) {
             log.warn("Probably: {}", errMissingTika);// $NON-NLS-1$
             response = errMissingTika;
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/util/HttpSSLProtocolSocketFactory.java b/src/core/src/main/java/org/apache/jmeter/util/HttpSSLProtocolSocketFactory.java
index 5714e62360..b8e7bb9077 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/HttpSSLProtocolSocketFactory.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/HttpSSLProtocolSocketFactory.java
@@ -68,10 +68,9 @@ public class HttpSSLProtocolSocketFactory
 
 
     private static void configureSocket(Socket socket){
-        if (!(socket instanceof SSLSocket)) {
+        if (!(socket instanceof SSLSocket sock)) {
             throw new IllegalArgumentException("Expected SSLSocket");
         }
-        SSLSocket sock = (SSLSocket) socket;
         if (!PROTOCOL_LIST.isEmpty()) {
             try {
                 sock.setEnabledProtocols(protocols);
@@ -115,7 +114,7 @@ public class HttpSSLProtocolSocketFactory
         }
     }
 
-    /*
+    /**
      * Wraps the socket in a slow SSL socket if necessary
      */
     private Socket wrapSocket(Socket sock){
diff --git a/src/core/src/main/java/org/apache/jmeter/util/JMeterUtils.java b/src/core/src/main/java/org/apache/jmeter/util/JMeterUtils.java
index 47912cc3d1..e5d22a318b 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/JMeterUtils.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/JMeterUtils.java
@@ -99,7 +99,7 @@ public class JMeterUtils implements UnitTestManager {
         private LazyPatternCacheHolder() {
             super();
         }
-        public static final PatternCacheLRU INSTANCE = new PatternCacheLRU(
+        private static final PatternCacheLRU INSTANCE = new PatternCacheLRU(
                 getPropDefault("oro.patterncache.size",1000), // $NON-NLS-1$
                 new Perl5Compiler());
     }
@@ -108,7 +108,7 @@ public class JMeterUtils implements UnitTestManager {
         private LazyJavaPatternCacheHolder() {
             super();
         }
-        public static final LoadingCache<Map.Entry<String, Integer>, java.util.regex.Pattern> INSTANCE =
+        private static final LoadingCache<Map.Entry<String, Integer>, java.util.regex.Pattern> INSTANCE =
                 Caffeine
                         .newBuilder()
                         .maximumSize(getPropDefault("jmeter.regex.patterncache.size", 1000))
diff --git a/src/core/src/main/java/org/apache/jmeter/util/JSR223TestElement.java b/src/core/src/main/java/org/apache/jmeter/util/JSR223TestElement.java
index c41e9f755a..5b042f33b6 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/JSR223TestElement.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/JSR223TestElement.java
@@ -89,10 +89,7 @@ public abstract class JSR223TestElement extends ScriptingTestElement
      * Initialization On Demand Holder pattern
      */
     private static class LazyHolder {
-        private LazyHolder() {
-            super();
-        }
-        public static final ScriptEngineManager INSTANCE = new ScriptEngineManager();
+        private static final ScriptEngineManager INSTANCE = new ScriptEngineManager();
     }
 
     /**
@@ -256,13 +253,13 @@ public abstract class JSR223TestElement extends ScriptingTestElement
             return compiledScript;
         } catch (ScriptCompilationInvocationTargetException e) {
             Throwable cause = e.getCause();
-            if (cause instanceof IOException) {
+            if (cause instanceof IOException ioException) {
                 cause.addSuppressed(new IllegalStateException("Unable to compile JSR223 script: " + newCacheKey));
-                throw (IOException) cause;
+                throw ioException;
             }
-            if (cause instanceof ScriptException) {
+            if (cause instanceof ScriptException scriptException) {
                 cause.addSuppressed(new IllegalStateException("Unable to compile JSR223 script: " + newCacheKey));
-                throw (ScriptException) cause;
+                throw scriptException;
             }
             throw e;
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/util/JsseSSLManager.java b/src/core/src/main/java/org/apache/jmeter/util/JsseSSLManager.java
index f4ca272c59..b31af47d3a 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/JsseSSLManager.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/JsseSSLManager.java
@@ -192,8 +192,7 @@ public class JsseSSLManager extends SSLManager {
         }
     }
 
-    /*
-     *
+    /**
      * Creates new SSL context
      *
      * @return SSL context
@@ -221,8 +220,7 @@ public class JsseSSLManager extends SSLManager {
 
         // Now wrap the default managers with our key manager
         for (int i = 0; i < managers.length; i++) {
-            if (managers[i] instanceof X509KeyManager) {
-                X509KeyManager manager = (X509KeyManager) managers[i];
+            if (managers[i] instanceof X509KeyManager manager) {
                 newManagers[i] = new WrappedX509KeyManager(manager, keys);
             } else {
                 newManagers[i] = managers[i];
@@ -291,7 +289,7 @@ public class JsseSSLManager extends SSLManager {
          * @param ks
          *            The KeyStore we derive our client certs and keys from
          */
-        public WrappedX509KeyManager(X509KeyManager parent, JmeterKeyStore ks) {
+        private WrappedX509KeyManager(X509KeyManager parent, JmeterKeyStore ks) {
             this.manager = parent;
             this.store = ks;
         }
diff --git a/src/core/src/main/java/org/apache/jmeter/util/SSLManager.java b/src/core/src/main/java/org/apache/jmeter/util/SSLManager.java
index 0c4823ebf6..50bb83b805 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/SSLManager.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/SSLManager.java
@@ -142,7 +142,7 @@ public abstract class SSLManager {
                  log.info("Total of {} aliases loaded OK from PKCS11", keyStore.getAliasCount());
               } else {
                  File initStore = new File(fileName);
-                 if (fileName.length() > 0 && initStore.exists()) {
+                 if (!fileName.isEmpty() && initStore.exists()) {
                      retryLoadKeys(initStore, true);
                      if (log.isInfoEnabled()) {
                          log.info("Total of {} aliases loaded OK from keystore {}",
diff --git a/src/core/src/main/java/org/apache/jmeter/util/ScriptingBeanInfoSupport.java b/src/core/src/main/java/org/apache/jmeter/util/ScriptingBeanInfoSupport.java
index e14b4e1249..46a4fdb90a 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/ScriptingBeanInfoSupport.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/ScriptingBeanInfoSupport.java
@@ -37,8 +37,8 @@ import org.apache.jmeter.testbeans.gui.TextAreaEditor;
  */
 public abstract class ScriptingBeanInfoSupport extends BeanInfoSupport {
 
-    static final String FALSE_AS_STRING = Boolean.FALSE.toString();
-    static final String TRUE_AS_STRING = Boolean.TRUE.toString();
+    static final String FALSE_AS_STRING = "false";
+    static final String TRUE_AS_STRING = "true";
 
     protected ScriptingBeanInfoSupport(Class<? extends TestBean> beanClass, String[] languageTags) {
         this(beanClass, languageTags, null);
@@ -49,7 +49,7 @@ public abstract class ScriptingBeanInfoSupport extends BeanInfoSupport {
         PropertyDescriptor p;
 
         p = property("scriptLanguage"); // $NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         if (JSR223TestElement.class.isAssignableFrom(beanClass) ) {
             p.setValue(DEFAULT, "groovy"); // $NON-NLS-1$
         } else {
@@ -65,14 +65,14 @@ public abstract class ScriptingBeanInfoSupport extends BeanInfoSupport {
                 new String[] { "scriptLanguage" }); // $NON-NLS-1$
 
         p = property("parameters"); // $NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, ""); // $NON-NLS-1$
 
         createPropertyGroup("parameterGroup", // $NON-NLS-1$
                 new String[] { "parameters" }); // $NON-NLS-1$
 
         p = property("filename"); // $NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, ""); // $NON-NLS-1$
         p.setPropertyEditorClass(FileEditor.class);
 
@@ -104,8 +104,8 @@ public abstract class ScriptingBeanInfoSupport extends BeanInfoSupport {
          */
         if (JSR223TestElement.class.isAssignableFrom(beanClass) ) {
             p = property("cacheKey"); // $NON-NLS-1$
-            p.setValue(NOT_UNDEFINED, Boolean.TRUE);
-            p.setValue(NOT_OTHER, Boolean.TRUE);
+            p.setValue(NOT_UNDEFINED, true);
+            p.setValue(NOT_OTHER, true);
             p.setValue(DEFAULT, TRUE_AS_STRING); // $NON-NLS-1$
             p.setPropertyEditorClass(JSR223ScriptCacheCheckboxEditor.class);
             p.setValue(TAGS, new String[]{TRUE_AS_STRING,FALSE_AS_STRING});
@@ -114,7 +114,7 @@ public abstract class ScriptingBeanInfoSupport extends BeanInfoSupport {
         }
 
         p = property("script"); // $NON-NLS-1$
-        p.setValue(NOT_UNDEFINED, Boolean.TRUE);
+        p.setValue(NOT_UNDEFINED, true);
         p.setValue(DEFAULT, ""); // $NON-NLS-1$
         p.setPropertyEditorClass(TextAreaEditor.class);
 
diff --git a/src/core/src/main/java/org/apache/jmeter/util/XPathUtil.java b/src/core/src/main/java/org/apache/jmeter/util/XPathUtil.java
index 7a9865f7ca..bfcf4dd151 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/XPathUtil.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/XPathUtil.java
@@ -625,38 +625,38 @@ public class XPathUtil {
         try {
             XObject xObject = XPathAPI.eval(doc, xPathExpression, getPrefixResolver(doc));
             switch (xObject.getType()) {
-            case XObject.CLASS_NODESET:
-                NodeList nodeList = xObject.nodelist();
-                final int len = (nodeList != null) ? nodeList.getLength() : 0;
-                log.debug("nodeList length {}", len);
-                // length == 0 means nodelist is null
-                if (len == 0) {
-                    log.debug("nodeList is null or empty. No match by xpath expression: {}", xPathExpression);
-                    result.setFailure(!isNegated);
-                    result.setFailureMessage("No Nodes Matched " + xPathExpression);
-                    return;
-                }
-                if (log.isDebugEnabled() && !isNegated) {
-                    for (int i = 0; i < len; i++) {
-                        log.debug("nodeList[{}]: {}", i, nodeList.item(i));
+                case XObject.CLASS_NODESET -> {
+                    NodeList nodeList = xObject.nodelist();
+                    final int len = (nodeList != null) ? nodeList.getLength() : 0;
+                    log.debug("nodeList length {}", len);
+                    // length == 0 means nodelist is null
+                    if (len == 0) {
+                        log.debug("nodeList is null or empty. No match by xpath expression: {}", xPathExpression);
+                        result.setFailure(!isNegated);
+                        result.setFailureMessage("No Nodes Matched " + xPathExpression);
+                        return;
+                    }
+                    if (log.isDebugEnabled() && !isNegated) {
+                        for (int i = 0; i < len; i++) {
+                            log.debug("nodeList[{}]: {}", i, nodeList.item(i));
+                        }
                     }
+                    result.setFailure(isNegated);
+                    if (isNegated) {
+                        result.setFailureMessage("Specified XPath was found... Turn off negate if this is not desired");
+                    }
+                }
+                case XObject.CLASS_BOOLEAN -> {
+                    boolean resultOfEval = xObject.bool();
+                    result.setFailure(isNegated ? resultOfEval : !resultOfEval);
+                    result.setFailureMessage(isNegated ?
+                            "Nodes Matched for " + xPathExpression
+                            : "No Nodes Matched for " + xPathExpression);
                 }
-                result.setFailure(isNegated);
-                if (isNegated) {
-                    result.setFailureMessage("Specified XPath was found... Turn off negate if this is not desired");
+                default -> {
+                    result.setFailure(true);
+                    result.setFailureMessage("Cannot understand: " + xPathExpression);
                 }
-                return;
-            case XObject.CLASS_BOOLEAN:
-                boolean resultOfEval = xObject.bool();
-                result.setFailure(isNegated ? resultOfEval : !resultOfEval);
-                result.setFailureMessage(isNegated ?
-                        "Nodes Matched for " + xPathExpression
-                        : "No Nodes Matched for " + xPathExpression);
-                return;
-            default:
-                result.setFailure(true);
-                result.setFailureMessage("Cannot understand: " + xPathExpression);
-                return;
             }
         } catch (TransformerException e) {
             result.setError(true);
diff --git a/src/core/src/main/java/org/apache/jmeter/util/keystore/JmeterKeyStore.java b/src/core/src/main/java/org/apache/jmeter/util/keystore/JmeterKeyStore.java
index 14212d0c5f..40eaf0d17a 100644
--- a/src/core/src/main/java/org/apache/jmeter/util/keystore/JmeterKeyStore.java
+++ b/src/core/src/main/java/org/apache/jmeter/util/keystore/JmeterKeyStore.java
@@ -149,9 +149,7 @@ public final class JmeterKeyStore {
             }
         }
 
-        /*
-         * Note: if is == null and no pkcs11 store is configured, the arrays will be empty
-         */
+        // Note: if is == null and no pkcs11 store is configured, the arrays will be empty
         this.names = aliasesList.toArray(new String[aliasesList.size()]);
     }
 
@@ -229,8 +227,7 @@ public final class JmeterKeyStore {
         for (List<?> entry : subjectAlternativeNames) {
             Object indexData = entry.get(0);
             Object data = entry.get(1);
-            if (indexData instanceof Integer) {
-                Integer generalNameIndex = (Integer) indexData;
+            if (indexData instanceof Integer generalNameIndex) {
                 String description = sanGeneralNameIndexToName(generalNameIndex);
                 String valueString = sanDataToString(data);
                 decodedEntries.add(Map.entry(description, valueString));
@@ -242,8 +239,8 @@ public final class JmeterKeyStore {
     }
 
     private static String sanDataToString(Object data) {
-        if (data instanceof String) {
-            return (String) data;
+        if (data instanceof String s) {
+            return s;
         }
         return Hex.encodeHexString((byte[]) data);
     }
diff --git a/src/core/src/main/java/org/apache/jmeter/visualizers/Sample.java b/src/core/src/main/java/org/apache/jmeter/visualizers/Sample.java
index c3ce2d3ed2..1e7aea728d 100644
--- a/src/core/src/main/java/org/apache/jmeter/visualizers/Sample.java
+++ b/src/core/src/main/java/org/apache/jmeter/visualizers/Sample.java
@@ -180,8 +180,8 @@ public class Sample implements Serializable, Comparable<Sample> {
 
     @Override
     public boolean equals(Object o){
-        return (o instanceof Sample) &&
-                (this.compareTo((Sample) o) == 0);
+        return (o instanceof Sample sample) &&
+                (this.compareTo(sample) == 0);
     }
 
     @Override
diff --git a/src/core/src/main/java/org/apache/jmeter/visualizers/TableSample.java b/src/core/src/main/java/org/apache/jmeter/visualizers/TableSample.java
index c862315746..c248a8feaa 100644
--- a/src/core/src/main/java/org/apache/jmeter/visualizers/TableSample.java
+++ b/src/core/src/main/java/org/apache/jmeter/visualizers/TableSample.java
@@ -130,8 +130,8 @@ public class TableSample implements Serializable, Comparable<TableSample> {
 
     @Override
     public boolean equals(Object o){
-        return (o instanceof TableSample) &&
-                (this.compareTo((TableSample) o) == 0);
+        return (o instanceof TableSample tableSample) &&
+                (this.compareTo(tableSample) == 0);
     }
 
     @Override
diff --git a/src/core/src/main/java/org/apache/jmeter/visualizers/gui/AbstractVisualizer.java b/src/core/src/main/java/org/apache/jmeter/visualizers/gui/AbstractVisualizer.java
index 68802c6723..c44dd9d58c 100644
--- a/src/core/src/main/java/org/apache/jmeter/visualizers/gui/AbstractVisualizer.java
+++ b/src/core/src/main/java/org/apache/jmeter/visualizers/gui/AbstractVisualizer.java
@@ -261,8 +261,7 @@ public abstract class AbstractVisualizer
     @Override
     public void modifyTestElement(TestElement c) {
         configureTestElement((AbstractListenerElement) c);
-        if (c instanceof ResultCollector) {
-            ResultCollector rc = (ResultCollector) c;
+        if (c instanceof ResultCollector rc) {
             rc.setErrorLogging(errorLogging.isSelected());
             rc.setSuccessOnlyLogging(successOnlyLogging.isSelected());
             rc.setFilename(getFile());
diff --git a/src/core/src/test/java/org/apache/jmeter/JMeterTest.java b/src/core/src/test/java/org/apache/jmeter/JMeterTest.java
index d4021dc1c9..25d76bd3d8 100644
--- a/src/core/src/test/java/org/apache/jmeter/JMeterTest.java
+++ b/src/core/src/test/java/org/apache/jmeter/JMeterTest.java
@@ -48,18 +48,21 @@ class JMeterTest extends JMeterTestCase implements JMeterSerialTest {
     @Test
     void testSuccessWhenJmxExists() throws IOException, ConfigurationException {
         File temp = File.createTempFile("testPlan", ".jmx");
-        String testPlan = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
-                + "<jmeterTestPlan version=\"1.2\" properties=\"5.0\" jmeter=\"5.2-SNAPSHOT\">\n" + "  <hashTree>\n"
-                + "    <TestPlan guiclass=\"TestPlanGui\" testclass=\"TestPlan\" testname=\"Test Plan\" enabled=\"true\">\n"
-                + "      <stringProp name=\"TestPlan.comments\"></stringProp>\n"
-                + "      <boolProp name=\"TestPlan.functional_mode\">false</boolProp>\n"
-                + "      <boolProp name=\"TestPlan.tearDown_on_shutdown\">true</boolProp>\n"
-                + "      <boolProp name=\"TestPlan.serialize_threadgroups\">false</boolProp>\n"
-                + "      <elementProp name=\"TestPlan.user_defined_variables\" elementType=\"Arguments\" guiclass=\"ArgumentsPanel\" "
-                + "testclass=\"Arguments\" testname=\"User Defined Variables\" enabled=\"true\">\n"
-                + "        <collectionProp name=\"Arguments.arguments\"/>\n" + "      </elementProp>\n"
-                + "      <stringProp name=\"TestPlan.user_define_classpath\"></stringProp></TestPlan>"
-                + "    <hashTree/></hashTree></jmeterTestPlan>";
+        String testPlan = """
+                <?xml version="1.0" encoding="UTF-8"?>
+                <jmeterTestPlan version="1.2" properties="5.0" jmeter="5.2-SNAPSHOT">
+                  <hashTree>
+                    <TestPlan guiclass="TestPlanGui" testclass="TestPlan" testname="Test Plan" enabled="true">
+                      <stringProp name="TestPlan.comments"></stringProp>
+                      <boolProp name="TestPlan.functional_mode">false</boolProp>
+                      <boolProp name="TestPlan.tearDown_on_shutdown">true</boolProp>
+                      <boolProp name="TestPlan.serialize_threadgroups">false</boolProp>
+                      <elementProp name="TestPlan.user_defined_variables" elementType="Arguments" guiclass="ArgumentsPanel" \
+                testclass="Arguments" testname="User Defined Variables" enabled="true">
+                        <collectionProp name="Arguments.arguments"/>
+                      </elementProp>
+                      <stringProp name="TestPlan.user_define_classpath"></stringProp></TestPlan>\
+                    <hashTree/></hashTree></jmeterTestPlan>""";
         try (FileOutputStream os = new FileOutputStream(temp);
                 Writer fw = new OutputStreamWriter(os, StandardCharsets.UTF_8);
                 BufferedWriter out = new BufferedWriter(fw)) {
@@ -77,33 +80,38 @@ class JMeterTest extends JMeterTestCase implements JMeterSerialTest {
     @Test
     void testFailureWithMissingPlugin() throws IOException {
         File temp = File.createTempFile("testPlan", ".jmx");
-        String testPlan = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
-                + "<jmeterTestPlan version=\"1.2\" properties=\"5.0\" jmeter=\"5.2-SNAPSHOT.20190506\">\n"
-                + "  <hashTree>\n"
-                + "    <TestPlan guiclass=\"TestPlanGui\" testclass=\"TestPlan\" testname=\"Test Plan\" enabled=\"true\">\n"
-                + "      <stringProp name=\"TestPlan.comments\"></stringProp>\n"
-                + "      <boolProp name=\"TestPlan.functional_mode\">false</boolProp>\n"
-                + "      <boolProp name=\"TestPlan.tearDown_on_shutdown\">true</boolProp>\n"
-                + "      <boolProp name=\"TestPlan.serialize_threadgroups\">false</boolProp>\n"
-                + "      <elementProp name=\"TestPlan.user_defined_variables\" elementType=\"Arguments\" "
-                + "guiclass=\"ArgumentsPanel\" testclass=\"Arguments\" testname=\"User Defined Variables\" enabled=\"true\">\n"
-                + "        <collectionProp name=\"Arguments.arguments\"/>\n" + "      </elementProp>\n"
-                + "      <stringProp name=\"TestPlan.user_define_classpath\"></stringProp>\n" + "    </TestPlan>\n"
-                + "    <hashTree>\n" + "      <hashTree>\n"
-                + "        <kg.apc.jmeter.samplers.DummySampler guiclass=\"kg.apc.jmeter.samplers.DummySamplerGui\" "
-                + "testclass=\"kg.apc.jmeter.samplers.DummySampler\" testname=\"jp@gc - Dummy Sampler\" enabled=\"true\">\n"
-                + "          <boolProp name=\"WAITING\">true</boolProp>\n"
-                + "          <boolProp name=\"SUCCESFULL\">true</boolProp>\n"
-                + "          <stringProp name=\"RESPONSE_CODE\">200</stringProp>\n"
-                + "          <stringProp name=\"RESPONSE_MESSAGE\">OK</stringProp>\n"
-                + "          <stringProp name=\"REQUEST_DATA\">{&quot;email&quot;:&quot;user1&quot;, &quot;password&quot;:&quot;password1&quot;};"
-                + "</stringProp>\n"
-                + "          <stringProp name=\"RESPONSE_DATA\">{&quot;successful&quot;: true, &quot;account_id&quot;:&quot;0123456789&quot;}</stringProp>\n"
-                + "          <stringProp name=\"RESPONSE_TIME\">${__Random(50,500)}</stringProp>\n"
-                + "          <stringProp name=\"LATENCY\">${__Random(1,50)}</stringProp>\n"
-                + "          <stringProp name=\"CONNECT\">${__Random(1,5)}</stringProp>\n"
-                + "        </kg.apc.jmeter.samplers.DummySampler></hashTree></hashTree>\n"
-                + "  </hashTree></jmeterTestPlan><hashTree/></hashTree>\n" + "</jmeterTestPlan>";
+        String testPlan = """
+                <?xml version="1.0" encoding="UTF-8"?>
+                <jmeterTestPlan version="1.2" properties="5.0" jmeter="5.2-SNAPSHOT.20190506">
+                  <hashTree>
+                    <TestPlan guiclass="TestPlanGui" testclass="TestPlan" testname="Test Plan" enabled="true">
+                      <stringProp name="TestPlan.comments"></stringProp>
+                      <boolProp name="TestPlan.functional_mode">false</boolProp>
+                      <boolProp name="TestPlan.tearDown_on_shutdown">true</boolProp>
+                      <boolProp name="TestPlan.serialize_threadgroups">false</boolProp>
+                      <elementProp name="TestPlan.user_defined_variables" elementType="Arguments" \
+                guiclass="ArgumentsPanel" testclass="Arguments" testname="User Defined Variables" enabled="true">
+                        <collectionProp name="Arguments.arguments"/>
+                      </elementProp>
+                      <stringProp name="TestPlan.user_define_classpath"></stringProp>
+                    </TestPlan>
+                    <hashTree>
+                      <hashTree>
+                        <kg.apc.jmeter.samplers.DummySampler guiclass="kg.apc.jmeter.samplers.DummySamplerGui" \
+                testclass="kg.apc.jmeter.samplers.DummySampler" testname="jp@gc - Dummy Sampler" enabled="true">
+                          <boolProp name="WAITING">true</boolProp>
+                          <boolProp name="SUCCESFULL">true</boolProp>
+                          <stringProp name="RESPONSE_CODE">200</stringProp>
+                          <stringProp name="RESPONSE_MESSAGE">OK</stringProp>
+                          <stringProp name="REQUEST_DATA">{&quot;email&quot;:&quot;user1&quot;, &quot;password&quot;:&quot;password1&quot;};\
+                </stringProp>
+                          <stringProp name="RESPONSE_DATA">{&quot;successful&quot;: true, &quot;account_id&quot;:&quot;0123456789&quot;}</stringProp>
+                          <stringProp name="RESPONSE_TIME">${__Random(50,500)}</stringProp>
+                          <stringProp name="LATENCY">${__Random(1,50)}</stringProp>
+                          <stringProp name="CONNECT">${__Random(1,5)}</stringProp>
+                        </kg.apc.jmeter.samplers.DummySampler></hashTree></hashTree>
+                  </hashTree></jmeterTestPlan><hashTree/></hashTree>
+                </jmeterTestPlan>""";
         try (FileOutputStream os = new FileOutputStream(temp);
                 Writer fw = new OutputStreamWriter(os, StandardCharsets.UTF_8);
                 BufferedWriter out = new BufferedWriter(fw)) {
diff --git a/src/core/src/test/java/org/apache/jmeter/engine/DistributedRunnerTest.java b/src/core/src/test/java/org/apache/jmeter/engine/DistributedRunnerTest.java
index cfab03df32..7254b3730b 100644
--- a/src/core/src/test/java/org/apache/jmeter/engine/DistributedRunnerTest.java
+++ b/src/core/src/test/java/org/apache/jmeter/engine/DistributedRunnerTest.java
@@ -86,7 +86,7 @@ public class DistributedRunnerTest {
         obj.exit(hosts);
     }
 
-    private void initRunner(DistributedRunnerEmul runner, List<String> hosts) {
+    private static void initRunner(DistributedRunnerEmul runner, List<String> hosts) {
         PrintStream origSystemOut = System.out;
         ByteArrayOutputStream catchingOut = new ByteArrayOutputStream();
         System.setOut(new PrintStream(catchingOut));
diff --git a/src/core/src/test/java/org/apache/jmeter/engine/LocalHostTest.java b/src/core/src/test/java/org/apache/jmeter/engine/LocalHostTest.java
index 956727f765..b79a4c1da1 100644
--- a/src/core/src/test/java/org/apache/jmeter/engine/LocalHostTest.java
+++ b/src/core/src/test/java/org/apache/jmeter/engine/LocalHostTest.java
@@ -41,7 +41,7 @@ public class LocalHostTest {
     public void testInterfaces() throws Exception {
         String interfaces = Collections
                 .list(NetworkInterface.getNetworkInterfaces()).stream()
-                .map(this::ifaceWithAddresses)
+                .map(LocalHostTest::ifaceWithAddresses)
                 .collect(Collectors.joining(", "));
         perr("Interfaces: {" + interfaces + "}");
         String externInterface = guessExternalIPv4Interface();
@@ -80,7 +80,7 @@ public class LocalHostTest {
                         .getInfo();
     }
 
-    private String ifaceWithAddresses(NetworkInterface iface) {
+    private static String ifaceWithAddresses(NetworkInterface iface) {
         return iface + " => ["
                 + iface.getInterfaceAddresses().stream()
                         .map(InterfaceAddress::toString)
@@ -99,7 +99,7 @@ public class LocalHostTest {
         }
     }
 
-    private InetAddress getLocalHost() throws UnknownHostException {
+    private static InetAddress getLocalHost() throws UnknownHostException {
         final String key = "java.rmi.server.hostname";
         String host = System.getProperties().getProperty(key); // $NON-NLS-1$
         perr(key + "=" + host);
diff --git a/src/core/src/test/java/org/apache/jmeter/engine/util/TestValueReplacer.java b/src/core/src/test/java/org/apache/jmeter/engine/util/TestValueReplacer.java
index 4a54e69a4a..7b1713eb31 100644
--- a/src/core/src/test/java/org/apache/jmeter/engine/util/TestValueReplacer.java
+++ b/src/core/src/test/java/org/apache/jmeter/engine/util/TestValueReplacer.java
@@ -127,7 +127,7 @@ public class TestValueReplacer extends JMeterTestCase {
         assertEquals("toto@${domainMatcher}", replaceWord("(005)", "toto@005"));
     }
 
-    private String replaceWord(String matchRegex, String testData) throws Exception {
+    private static String replaceWord(String matchRegex, String testData) throws Exception {
         TestPlan plan = new TestPlan();
         plan.addParameter("domainMatcher", matchRegex);
         ValueReplacer replacer = new ValueReplacer(plan);
@@ -160,7 +160,7 @@ public class TestValueReplacer extends JMeterTestCase {
         assertEquals(input, element.getPropertyAsString("domain"));
     }
 
-    /*
+    /**
      * This test should be compared with the one above.
      * Here, the string contains a valid variable reference, so all
      * backslashes are also processed.
diff --git a/src/core/src/test/java/org/apache/jmeter/gui/logging/TestGuiLogEventAppender.java b/src/core/src/test/java/org/apache/jmeter/gui/logging/TestGuiLogEventAppender.java
index 246c44af34..887f5aae00 100644
--- a/src/core/src/test/java/org/apache/jmeter/gui/logging/TestGuiLogEventAppender.java
+++ b/src/core/src/test/java/org/apache/jmeter/gui/logging/TestGuiLogEventAppender.java
@@ -45,7 +45,7 @@ public class TestGuiLogEventAppender {
 
     private static List<String> log4j2LevelErrorMessages = Collections.synchronizedList(new ArrayList<>());
 
-    /*
+    /**
      * Configure logging with GuiLogEventAppender for root logger, and override the handler of GuiLogEventAppender
      * to see if there's any log4j2 AppenderControl level error (e.g, "Recursive call to appender gui-log-event").
      */
@@ -97,7 +97,7 @@ public class TestGuiLogEventAppender {
         log4j2LevelErrorMessages.clear();
     }
 
-    /*
+    /**
      * Make simple logs and see whether there's any log4j2 AppenderControl level error (e.g, "Recursive call to
      * appender gui-log-event").
      * For example, if GuiLogEventAppender meets an exception while accessing GuiPackage class due to static member
diff --git a/src/core/src/test/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumerTest.java b/src/core/src/test/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumerTest.java
index d236771725..d0eb6e42b2 100644
--- a/src/core/src/test/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumerTest.java
+++ b/src/core/src/test/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumerTest.java
@@ -73,7 +73,7 @@ public class ErrorsSummaryConsumerTest {
         assertEquals(Long.valueOf(2), info.getData());
     }
 
-    private Sample createSample(boolean success) {
+    private static Sample createSample(boolean success) {
         SampleMetadata metadata = new SampleMetadata(',', CSVSaveService.SUCCESSFUL);
         return new Sample(0, metadata, String.valueOf(success));
     }
diff --git a/src/core/src/test/java/org/apache/jmeter/report/processor/graph/impl/CustomGraphConsumerTest.java b/src/core/src/test/java/org/apache/jmeter/report/processor/graph/impl/CustomGraphConsumerTest.java
index 952574d395..c594f1603d 100644
--- a/src/core/src/test/java/org/apache/jmeter/report/processor/graph/impl/CustomGraphConsumerTest.java
+++ b/src/core/src/test/java/org/apache/jmeter/report/processor/graph/impl/CustomGraphConsumerTest.java
@@ -160,7 +160,7 @@ public class CustomGraphConsumerTest {
     }
 
     // Create a static SampleMetadataObject
-    private SampleMetadata createTestMetaData() {
+    private static SampleMetadata createTestMetaData() {
         String columnsString = "timeStamp,elapsed,label,responseCode,responseMessage,threadName,success,failureMessage,bytes,sentBytes,"
                 + "grpThreads,allThreads,URL,Latency,IdleTime,Connect,\"stream\",\"aws_region\",\"bitrate\",\"ulp_buffer_fill\",\"ulp_lag_time\","
                 + "\"ulp_play_time\",\"ulp_lag_ratio\",\"lag_ratio_wo_bf\",\"ulp_dwn_time\",\"ulp_hits\",\"ulp_avg_chunk_time\","
diff --git a/src/core/src/test/java/org/apache/jmeter/samplers/TestDataStrippingSampleSender.java b/src/core/src/test/java/org/apache/jmeter/samplers/TestDataStrippingSampleSender.java
index b14f85f273..47fc2ec6d7 100644
--- a/src/core/src/test/java/org/apache/jmeter/samplers/TestDataStrippingSampleSender.java
+++ b/src/core/src/test/java/org/apache/jmeter/samplers/TestDataStrippingSampleSender.java
@@ -62,7 +62,7 @@ class TestDataStrippingSampleSender extends JMeterTestCase implements JMeterSeri
         assertEquals(nextSender.getResult(), sample);
     }
 
-    private void assertResultsHaveContent(String content, SampleResult sample) {
+    private static void assertResultsHaveContent(String content, SampleResult sample) {
         assertEquals(content, sample.getResponseDataAsString());
         for (SampleResult subResult : sample.getSubResults()) {
             assertResultsHaveContent(content, subResult);
diff --git a/src/core/src/test/java/org/apache/jmeter/samplers/TestSampleResult.java b/src/core/src/test/java/org/apache/jmeter/samplers/TestSampleResult.java
index a551a5287f..e18738b317 100644
--- a/src/core/src/test/java/org/apache/jmeter/samplers/TestSampleResult.java
+++ b/src/core/src/test/java/org/apache/jmeter/samplers/TestSampleResult.java
@@ -102,8 +102,8 @@ class TestSampleResult implements JMeterSerialTest {
     private LogRecordingDelegatingLogger recordLogger;
 
     private void divertLog() {// N.B. This needs to divert the log for SampleResult
-        if (SampleResult.log instanceof LogRecordingDelegatingLogger) {
-            recordLogger = (LogRecordingDelegatingLogger) SampleResult.log;
+        if (SampleResult.log instanceof LogRecordingDelegatingLogger logRecordingDelegatingLogger) {
+            recordLogger = logRecordingDelegatingLogger;
         } else {
             recordLogger = new LogRecordingDelegatingLogger(SampleResult.log);
             SampleResult.log = recordLogger;
@@ -193,11 +193,11 @@ class TestSampleResult implements JMeterSerialTest {
         }
     }
 
-    private void testSubResults(boolean nanoTime, long pause) throws Exception {
+    private static void testSubResults(boolean nanoTime, long pause) throws Exception {
         testSubResults(nanoTime, 0L, pause); // Don't use nanoThread
     }
 
-    private void testSubResults(boolean nanoTime, long nanoThreadSleep, long pause) throws Exception {
+    private static void testSubResults(boolean nanoTime, long nanoThreadSleep, long pause) throws Exception {
         // This test tries to emulate a http sample, with two
         // subsamples, representing images that are downloaded for the
         // page representing the first sample.
@@ -339,7 +339,7 @@ class TestSampleResult implements JMeterSerialTest {
 
     // sleep and return how long we actually slept
     // may be rather longer if the system is busy
-    private long sleep(long ms) throws InterruptedException {
+    private static long sleep(long ms) throws InterruptedException {
         long start = System.currentTimeMillis();
         Thread.sleep(ms);
         return System.currentTimeMillis() - start;
diff --git a/src/core/src/test/java/org/apache/jmeter/save/TestCSVSaveService.java b/src/core/src/test/java/org/apache/jmeter/save/TestCSVSaveService.java
index cb9d959f17..2bcf146922 100644
--- a/src/core/src/test/java/org/apache/jmeter/save/TestCSVSaveService.java
+++ b/src/core/src/test/java/org/apache/jmeter/save/TestCSVSaveService.java
@@ -34,12 +34,12 @@ import org.junit.jupiter.api.Test;
 
 public class TestCSVSaveService extends JMeterTestCase {
 
-    private void checkSplitString(String input, char delim, String[] expected) throws Exception {
+    private static void checkSplitString(String input, char delim, String[] expected) throws Exception {
         String[] out = CSVSaveService.csvSplitString(input, delim);
         checkStrings(expected, out);
     }
 
-    private void checkStrings(String[] expected, String[] out) {
+    private static void checkStrings(String[] expected, String[] out) {
         assertEquals(expected.length, out.length, "Incorrect number of strings returned");
         for(int i = 0; i < out.length; i++){
            assertEquals(expected[i], out[i], "Incorrect entry returned");
diff --git a/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestBooleanPropertyEditor.java b/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestBooleanPropertyEditor.java
index ed4a10ffbe..6409d3f473 100644
--- a/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestBooleanPropertyEditor.java
+++ b/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestBooleanPropertyEditor.java
@@ -33,7 +33,7 @@ import org.junit.jupiter.api.Test;
  */
 public class TestBooleanPropertyEditor {
 
-     // N.B. These values are NOT the same as Boolean.FALSE|TRUE.toString()
+     // N.B. These values are NOT the same as false|TRUE.toString()
      // which returns lower-case only.
      // The getAsText() method converts the result to mixed case.
     private static final String FALSE = "False"; // $NON-NLS-1$
@@ -51,14 +51,14 @@ public class TestBooleanPropertyEditor {
         testBooleanEditor(propertyEditor);
     }
 
-    private void testBooleanEditor(PropertyEditor propertyEditor) {
+    private static void testBooleanEditor(PropertyEditor propertyEditor) {
         assertNotNull(propertyEditor, "Expected to find property editor");
         String[] tags = propertyEditor.getTags();
         assertEquals(2, tags.length);
         assertEquals(TRUE, tags[0]);
         assertEquals(FALSE, tags[1]);
 
-        propertyEditor.setValue(Boolean.FALSE);
+        propertyEditor.setValue(false);
         assertEquals(FALSE, propertyEditor.getAsText());
         propertyEditor.setAsText(FALSE);
         assertEquals(FALSE, propertyEditor.getAsText());
@@ -69,7 +69,7 @@ public class TestBooleanPropertyEditor {
         propertyEditor.setAsText("FALSE");
         assertEquals(FALSE, propertyEditor.getAsText());
 
-        propertyEditor.setValue(Boolean.TRUE);
+        propertyEditor.setValue(true);
         assertEquals(TRUE, propertyEditor.getAsText());
         propertyEditor.setAsText(TRUE);
         assertEquals(TRUE, propertyEditor.getAsText());
diff --git a/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestComboStringEditor.java b/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestComboStringEditor.java
index c0aae9b63b..f1d94eeef5 100644
--- a/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestComboStringEditor.java
+++ b/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestComboStringEditor.java
@@ -24,12 +24,12 @@ import org.junit.jupiter.api.Test;
 
 public class TestComboStringEditor {
 
-    private void testSetGet(ComboStringEditor e, Object value) throws Exception {
+    private static void testSetGet(ComboStringEditor e, Object value) throws Exception {
         e.setValue(value);
         assertEquals(value, e.getValue());
     }
 
-    private void testSetGetAsText(ComboStringEditor e, String text) throws Exception {
+    private static void testSetGetAsText(ComboStringEditor e, String text) throws Exception {
         e.setAsText(text);
         assertEquals(text, e.getAsText());
     }
diff --git a/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestFieldStringEditor.java b/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestFieldStringEditor.java
index 573de5b5ca..b0ab172d06 100644
--- a/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestFieldStringEditor.java
+++ b/src/core/src/test/java/org/apache/jmeter/testbeans/gui/TestFieldStringEditor.java
@@ -23,12 +23,12 @@ import org.junit.jupiter.api.Test;
 
 public class TestFieldStringEditor {
 
-    private void testSetGet(ComboStringEditor e, Object value) throws Exception {
+    private static void testSetGet(ComboStringEditor e, Object value) throws Exception {
         e.setValue(value);
         assertEquals(value, e.getValue());
     }
 
-    private void testSetGetAsText(ComboStringEditor e, String text) throws Exception {
+    private static void testSetGetAsText(ComboStringEditor e, String text) throws Exception {
         e.setAsText(text);
         assertEquals(text, e.getAsText());
     }
diff --git a/src/core/src/test/java/org/apache/jmeter/testelement/property/PackageTest.java b/src/core/src/test/java/org/apache/jmeter/testelement/property/PackageTest.java
index 3874051209..4925006620 100644
--- a/src/core/src/test/java/org/apache/jmeter/testelement/property/PackageTest.java
+++ b/src/core/src/test/java/org/apache/jmeter/testelement/property/PackageTest.java
@@ -69,7 +69,7 @@ class PackageTest {
         assertEquals("username=password", prop.getStringValue());
     }
 
-    private void checkEquals(JMeterProperty jp1, JMeterProperty jp2) {
+    private static void checkEquals(JMeterProperty jp1, JMeterProperty jp2) {
         assertEquals(jp1, jp2);
         assertEquals(jp2, jp1);
         assertEquals(jp1, jp1);
@@ -77,7 +77,7 @@ class PackageTest {
         assertEquals(jp1.hashCode(), jp2.hashCode());
     }
 
-    private void checkNotEquals(JMeterProperty jp1, JMeterProperty jp2) {
+    private static void checkNotEquals(JMeterProperty jp1, JMeterProperty jp2) {
         assertEquals(jp1, jp1);
         assertEquals(jp2, jp2);
         assertNotEquals(jp1, jp2);
diff --git a/src/core/src/test/java/org/apache/jmeter/threads/TestJMeterThread.java b/src/core/src/test/java/org/apache/jmeter/threads/TestJMeterThread.java
index fcd3a5f6d2..4be76a4488 100644
--- a/src/core/src/test/java/org/apache/jmeter/threads/TestJMeterThread.java
+++ b/src/core/src/test/java/org/apache/jmeter/threads/TestJMeterThread.java
@@ -168,20 +168,20 @@ class TestJMeterThread {
         assertTrue(duration <= maxDuration, "Test plan should not run for longer than duration");
     }
 
-    private LoopController createLoopController() {
+    private static LoopController createLoopController() {
         LoopController result = new LoopController();
         result.setLoops(LoopController.INFINITE_LOOP_COUNT);
         result.setEnabled(true);
         return result;
     }
 
-    private DummySampler createSampler() {
+    private static DummySampler createSampler() {
         DummySampler result = new DummySampler();
         result.setName("Call me");
         return result;
     }
 
-    private Timer createConstantTimer(long delay) {
+    private static Timer createConstantTimer(long delay) {
         DummyTimer timer = new DummyTimer();
         timer.setEnabled(true);
         timer.setDelay(delay);
diff --git a/src/core/src/test/java/org/apache/jmeter/threads/TestUnmodifiableJMeterVariables.java b/src/core/src/test/java/org/apache/jmeter/threads/TestUnmodifiableJMeterVariables.java
index 4b04e6bd1a..0ceb7ecb59 100644
--- a/src/core/src/test/java/org/apache/jmeter/threads/TestUnmodifiableJMeterVariables.java
+++ b/src/core/src/test/java/org/apache/jmeter/threads/TestUnmodifiableJMeterVariables.java
@@ -108,7 +108,7 @@ public class TestUnmodifiableJMeterVariables {
         assertThrowsUnsupportedOperation(iterator::remove);
     }
 
-    private void assertThrowsUnsupportedOperation(Executable executable) {
+    private static void assertThrowsUnsupportedOperation(Executable executable) {
         assertThrows(
                 UnsupportedOperationException.class,
                 executable
@@ -120,7 +120,7 @@ public class TestUnmodifiableJMeterVariables {
         assertEquals(iteratorToMap(vars.getIterator()), iteratorToMap(unmodifiables.getIterator()));
     }
 
-    private <K, V> Map<K, V> iteratorToMap(Iterator<Map.Entry<K, V>> it) {
+    private static <K, V> Map<K, V> iteratorToMap(Iterator<Map.Entry<K, V>> it) {
         Map<K, V> result = new HashMap<>();
         while (it.hasNext()) {
             Map.Entry<K, V> entry = it.next();
diff --git a/src/core/src/test/java/org/apache/jmeter/util/SecurityProviderLoaderTest.java b/src/core/src/test/java/org/apache/jmeter/util/SecurityProviderLoaderTest.java
index aef5a00de0..5f5451507a 100644
--- a/src/core/src/test/java/org/apache/jmeter/util/SecurityProviderLoaderTest.java
+++ b/src/core/src/test/java/org/apache/jmeter/util/SecurityProviderLoaderTest.java
@@ -122,7 +122,7 @@ public class SecurityProviderLoaderTest {
         assertEquals(provider, providersAfter[expectedInsertPosition(position, providersAfter)]);
     }
 
-    private int expectedInsertPosition(int position, Provider[] providersAfter) {
+    private static int expectedInsertPosition(int position, Provider[] providersAfter) {
         if (position == 0) {
             return providersAfter.length - 1;
         }
diff --git a/src/core/src/testFixtures/java/org/apache/jmeter/junit/JMeterTestCase.java b/src/core/src/testFixtures/java/org/apache/jmeter/junit/JMeterTestCase.java
index 475b012a45..024aba096c 100644
--- a/src/core/src/testFixtures/java/org/apache/jmeter/junit/JMeterTestCase.java
+++ b/src/core/src/testFixtures/java/org/apache/jmeter/junit/JMeterTestCase.java
@@ -99,7 +99,7 @@ public abstract class JMeterTestCase {
     // Helper method to find a file
     protected static File findTestFile(String file) {
         File f = new File(file);
-        if (filePrefix.length() > 0 && !f.isAbsolute()) {
+        if (!filePrefix.isEmpty() && !f.isAbsolute()) {
             f = new File(filePrefix, file);// Add the offset
         }
         return f;
@@ -108,7 +108,7 @@ public abstract class JMeterTestCase {
     // Helper method to find a test path
     protected static String findTestPath(String file) {
         File f = new File(file);
-        if (filePrefix.length() > 0 && !f.isAbsolute()) {
+        if (!filePrefix.isEmpty() && !f.isAbsolute()) {
             return filePrefix + file;// Add the offset
         }
         return file;
diff --git a/src/core/src/testFixtures/java/org/apache/jmeter/resources/PackageTest.java b/src/core/src/testFixtures/java/org/apache/jmeter/resources/PackageTest.java
index f90cff518e..525a412ab4 100644
--- a/src/core/src/testFixtures/java/org/apache/jmeter/resources/PackageTest.java
+++ b/src/core/src/testFixtures/java/org/apache/jmeter/resources/PackageTest.java
@@ -105,22 +105,18 @@ public class PackageTest {
                     int equ = s.indexOf('=');
                     String key = s.substring(0, equ);
                     if (resourcePrefix.equals(MESSAGES)){// Only relevant for messages
-                        /*
-                         * JMeterUtils.getResString() converts space to _ and lowercases
-                         * the key, so make sure all keys pass the test
-                         */
+                        // JMeterUtils.getResString() converts space to _ and lowercases
+                        // the key, so make sure all keys pass the test
                         if (key.contains(" ") || !key.toLowerCase(java.util.Locale.ENGLISH).equals(key)) {
                             failures.add("Invalid key for JMeterUtils " + key);
                         }
                     }
                     String val = s.substring(equ + 1);
                     l.add(key); // Store the key
-                    /*
-                     * Now check for invalid message format: if string contains {0}
-                     * and ' there may be a problem, so do a format with dummy
-                     * parameters and check if there is a { in the output. A bit
-                     * crude, but should be enough for now.
-                     */
+                    // Now check for invalid message format: if string contains {0}
+                    // and ' there may be a problem, so do a format with dummy
+                    // parameters and check if there is a { in the output. A bit
+                    // crude, but should be enough for now.
                     if (val.contains("{0}") && val.contains("'")) {
                         String m = java.text.MessageFormat.format(val, DUMMY_PARAMS);
                         if (m.contains("{")) {
@@ -141,7 +137,7 @@ public class PackageTest {
     }
 
     // Helper method to construct resource name
-    private String getResName(String lang, String resourcePrefix) {
+    private static String getResName(String lang, String resourcePrefix) {
         if (lang.isEmpty()) {
             return resourcePrefix+".properties";
         } else {
@@ -258,9 +254,9 @@ public class PackageTest {
         }
     }
 
-    /*
+    /**
      * Use a suite to ensure that the default is done first
-    */
+     */
     public static Collection<Arguments> languagesAndPrefixes() {
         Collection<Arguments> res = new ArrayList<>();
         String[] languages = JMeterMenuBar.getLanguages();
@@ -300,8 +296,8 @@ public class PackageTest {
         assertEquals(0, missingLabelsPerBundle.size(), missingLabelsPerBundle.size()+" missing labels, labels missing:"+printLabels(missingLabelsPerBundle));
     }
 
-    private void checkMessagesForLanguage(Map<String, Map<String, String>> missingLabelsPerBundle,
-                                          Properties messages, String bundlePath, String language)
+    private static void checkMessagesForLanguage(Map<String, Map<String, String>> missingLabelsPerBundle,
+            Properties messages, String bundlePath, String language)
             throws IOException {
         Properties messagesFr = new Properties();
         String languageBundle = bundlePath+"_"+language+ ".properties";
@@ -340,7 +336,7 @@ public class PackageTest {
         }
     }
 
-    private String printLabels(Map<String, Map<String, String>> missingLabelsPerBundle) {
+    private static String printLabels(Map<String, Map<String, String>> missingLabelsPerBundle) {
         StringBuilder builder = new StringBuilder();
         for (Map.Entry<String, Map<String, String>> entry : missingLabelsPerBundle.entrySet()) {
             builder.append("Missing labels in bundle:")
diff --git a/src/dist-check/src/test/java/org/apache/jmeter/control/TestSwitchController.java b/src/dist-check/src/test/java/org/apache/jmeter/control/TestSwitchController.java
index 246c803f21..63c30a56fe 100644
--- a/src/dist-check/src/test/java/org/apache/jmeter/control/TestSwitchController.java
+++ b/src/dist-check/src/test/java/org/apache/jmeter/control/TestSwitchController.java
@@ -38,7 +38,7 @@ import org.junit.jupiter.api.Test;
 public class TestSwitchController extends JMeterTestCase {
 
     // Get next sample and its name
-    private String nextName(GenericController c) {
+    private static String nextName(GenericController c) {
         Sampler s = c.next();
         String n;
         if (s == null) {
@@ -89,12 +89,12 @@ public class TestSwitchController extends JMeterTestCase {
         runSimpleTest2("X", "one", "Default"); // should match the default entry
     }
 
-    private void runSimpleTests(String cond, String exp) throws Exception {
+    private static void runSimpleTests(String cond, String exp) throws Exception {
         runSimpleTest(cond, exp);
         runSimpleTest2(cond, exp, "one");
     }
 
-    /*
+    /**
      *  Simple test with single Selection controller
      *  Generic Controller
      *  + Sampler "before"
@@ -105,7 +105,7 @@ public class TestSwitchController extends JMeterTestCase {
      *  + + Sampler "three"
      *  + Sampler "after"
      */
-    private void runSimpleTest(String cond, String exp) throws Exception {
+    private static void runSimpleTest(String cond, String exp) throws Exception {
         GenericController controller = new GenericController();
 
         SwitchController switch_cont = new SwitchController();
@@ -135,7 +135,7 @@ public class TestSwitchController extends JMeterTestCase {
 
     // Selection controller with two sub-controllers, but each has only 1
     // child
-    /*
+    /**
      * Controller
      * + Before
      * + Switch (cond)
@@ -147,7 +147,7 @@ public class TestSwitchController extends JMeterTestCase {
      * + + + three
      * + After
      */
-    private void runSimpleTest2(String cond, String exp, String sub1Name) throws Exception {
+    private static void runSimpleTest2(String cond, String exp, String sub1Name) throws Exception {
         GenericController controller = new GenericController();
         GenericController sub_1 = new GenericController();
         GenericController sub_2 = new GenericController();
@@ -193,7 +193,7 @@ public class TestSwitchController extends JMeterTestCase {
         runTest2("2", new String[]{"three", "four"});
     }
 
-    /*
+    /**
      * Test:
      * Before
      * Selection Controller
@@ -211,7 +211,7 @@ public class TestSwitchController extends JMeterTestCase {
      * cond  = Switch condition
      * exp[] = expected results
      */
-    private void runTest2(String cond, String[] exp) throws Exception {
+    private static void runTest2(String cond, String[] exp) throws Exception {
         int loops = 3;
         LoopController controller = new LoopController();
         controller.setLoops(loops);
@@ -252,7 +252,7 @@ public class TestSwitchController extends JMeterTestCase {
         assertNull(nextName(controller), "Loops:" + loops);
     }
 
-    /*
+    /**
      * N.B. Requires ApacheJMeter_functions.jar to be on the classpath,
      * otherwise the function cannot be resolved.
      */
diff --git a/src/dist-check/src/test/java/org/apache/jmeter/functions/ComponentReferenceFunctionTest.java b/src/dist-check/src/test/java/org/apache/jmeter/functions/ComponentReferenceFunctionTest.java
index ed3b56c694..4b50aec8ff 100644
--- a/src/dist-check/src/test/java/org/apache/jmeter/functions/ComponentReferenceFunctionTest.java
+++ b/src/dist-check/src/test/java/org/apache/jmeter/functions/ComponentReferenceFunctionTest.java
@@ -73,14 +73,14 @@ public class ComponentReferenceFunctionTest extends JMeterTestCase {
         }
     }
 
-    /*
+    /**
      * Test Functions - create the suite of tests
      */
     static Collection<Function> functions() throws Throwable {
         return Holder.FUNCTIONS;
     }
 
-    private Element getBodyFromXMLDocument(InputStream stream)
+    private static Element getBodyFromXMLDocument(InputStream stream)
             throws ParserConfigurationException, SAXException, IOException {
         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
         dbf.setIgnoringElementContentWhitespace(true);
@@ -108,10 +108,10 @@ public class ComponentReferenceFunctionTest extends JMeterTestCase {
                 for (int j = 0; j < components.getLength(); j++) {
                     org.w3c.dom.Element comp = (org.w3c.dom.Element)
                             components.item(j);
-                    funcTitles.put(comp.getAttribute("name"), Boolean.FALSE);
+                    funcTitles.put(comp.getAttribute("name"), false);
                     String tag = comp.getAttribute("tag");
                     if (StringUtilities.isNotEmpty(tag)){
-                        funcTitles.put(tag, Boolean.FALSE);
+                        funcTitles.put(tag, false);
                     }
                 }
             }
@@ -123,17 +123,17 @@ public class ComponentReferenceFunctionTest extends JMeterTestCase {
         Assertions.assertEquals("[]", JMeterTest.keysWithFalseValues(funcTitles).toString(), "Should not have any names left over in funcTitles");
     }
 
-    /*
+    /**
      * run the function test
      */
     @ParameterizedTest
     @MethodSource("functions")
     public void runFunction(Function funcItem) throws Exception {
-        if (funcTitles.size() > 0) {
+        if (!funcTitles.isEmpty()) {
             String title = funcItem.getReferenceKey();
             boolean ct = funcTitles.containsKey(title);
             if (ct) {
-                funcTitles.put(title, Boolean.TRUE);// For detecting extra entries
+                funcTitles.put(title, true);// For detecting extra entries
             }
             // Is this a work in progress ?
             if (!title.contains("(ALPHA") && !title.contains("(EXPERIMENTAL")) {
@@ -147,7 +147,7 @@ public class ComponentReferenceFunctionTest extends JMeterTestCase {
         }
     }
 
-    /*
+    /**
      * Check that function descriptions are OK
      */
     @ParameterizedTest
diff --git a/src/dist-check/src/test/java/org/apache/jmeter/gui/action/TestLoad.java b/src/dist-check/src/test/java/org/apache/jmeter/gui/action/TestLoad.java
index 63b6018ee4..78e6aac47a 100644
--- a/src/dist-check/src/test/java/org/apache/jmeter/gui/action/TestLoad.java
+++ b/src/dist-check/src/test/java/org/apache/jmeter/gui/action/TestLoad.java
@@ -82,7 +82,7 @@ public class TestLoad extends JMeterTestCase {
         assertTree(tree, parent, testFile);
     }
 
-    private void assertTree(HashTree tree, String parent, File testFile) throws Exception {
+    private static void assertTree(HashTree tree, String parent, File testFile) throws Exception {
         assertNotNull(tree, parent+": "+ testFile.getName()+" caused null tree: ");
         final Object object = tree.getArray()[0];
         final String name = testFile.getName();
@@ -92,7 +92,7 @@ public class TestLoad extends JMeterTestCase {
         }
     }
 
-    private HashTree getTree(File f) throws Exception {
+    private static HashTree getTree(File f) throws Exception {
         HashTree tree = SaveService.loadTree(f);
         return tree;
     }
diff --git a/src/dist-check/src/test/java/org/apache/jmeter/junit/JMeterTest.java b/src/dist-check/src/test/java/org/apache/jmeter/junit/JMeterTest.java
index 4e64f94ba2..2aca34f3e1 100644
--- a/src/dist-check/src/test/java/org/apache/jmeter/junit/JMeterTest.java
+++ b/src/dist-check/src/test/java/org/apache/jmeter/junit/JMeterTest.java
@@ -138,7 +138,7 @@ public class JMeterTest extends JMeterTestCase {
         Locale.setDefault(DEFAULT_LOCALE);
     }
 
-    /*
+    /**
      * Extract titles from component_reference.xml
      */
     @BeforeAll
@@ -157,13 +157,13 @@ public class JMeterTest extends JMeterTestCase {
                             components.item(j);
                     String nm = comp.getAttribute("name");
                     if (!nm.equals("SSL Manager")) {// Not a true GUI component
-                        guiTitles.put(nm.replace(' ', '_'), Boolean.FALSE);
+                        guiTitles.put(nm.replace(' ', '_'), false);
                     }
                 }
             }
         }
         // Add titles that don't need to be documented
-        guiTitles.put("Example Sampler", Boolean.FALSE);
+        guiTitles.put("Example Sampler", false);
     }
 
     /**
@@ -184,7 +184,7 @@ public class JMeterTest extends JMeterTestCase {
         return body;
     }
 
-    /*
+    /**
      * Extract titles from component_reference.xml
      */
     @BeforeAll
@@ -204,7 +204,7 @@ public class JMeterTest extends JMeterTestCase {
                             components.item(j);
                     String tag = comp.getAttribute("tag");
                     if (StringUtilities.isNotEmpty(tag)){
-                        guiTags.put(tag, Boolean.FALSE);
+                        guiTags.put(tag, false);
                     }
                 }
             }
@@ -213,7 +213,7 @@ public class JMeterTest extends JMeterTestCase {
 
     public static<T> List<T> keysWithFalseValues(Map<? extends T, Boolean> map) {
         return map.entrySet().stream()
-                .filter(e -> !e.getValue().equals(Boolean.TRUE))
+                .filter(e -> !e.getValue().equals(true))
                 .map(Map.Entry::getKey)
                 .sorted()
                 .collect(Collectors.toList());
@@ -251,7 +251,7 @@ public class JMeterTest extends JMeterTestCase {
         return components;
     }
 
-    /*
+    /**
      * Test GUI elements - create the suite of tests
      */
     static Collection<GuiComponentHolder> guiComponents() throws Throwable {
@@ -264,7 +264,7 @@ public class JMeterTest extends JMeterTestCase {
         return components;
     }
 
-    /*
+    /**
... 6739 lines suppressed ...