[GitHub] [ignite-3] alievmirza commented on a change in pull request #327: review pmd check rules

[GitBox <gi...@apache.org>]

alievmirza commented on a change in pull request #327:
URL: https://github.com/apache/ignite-3/pull/327#discussion_r705368917



##########
File path: check-rules/errorprone.xml
##########
@@ -0,0 +1,3721 @@
+<?xml version="1.0"?>
+
+<ruleset name="Error Prone"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+    <description>
+        Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
+    </description>
+
+    <rule name="AssignmentInOperand"
+          language="java"
+          since="1.03"
+          message="Avoid assignments in operands"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentInOperandRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmentinoperand">
+        <description>
+            Avoid assignments in operands; this can make code more complicated and harder to read.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    if ((x = getX()) == 3) {
+      System.out.println("3!");
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AssignmentToNonFinalStatic"
+          language="java"
+          since="2.2"
+          message="Possible unsafe assignment to a non-final static field in a constructor."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentToNonFinalStaticRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmenttononfinalstatic">
+        <description>
+            Identifies a possible unsafe usage of a static field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class StaticField {
+   static int x;
+   public FinalFields(int y) {
+    x = y; // unsafe
+   }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAccessibilityAlteration"
+          language="java"
+          since="4.1"
+          message="You should not modify visibility of class or methods using getDeclaredConstructors(), getDeclaredConstructor(Class[]), setAccessible() or PrivilegedAction."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidaccessibilityalteration">
+        <description>
+            Methods such as getDeclaredConstructors(), getDeclaredConstructor(Class[]) and setAccessible(),
+            as the interface PrivilegedAction, allow for the runtime alteration of variable, class, or
+            method visibility, even if they are private. This violates the principle of encapsulation.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimaryExpression[
+(
+(PrimarySuffix[
+        ends-with(@Image,'getDeclaredConstructors')
+                or
+        ends-with(@Image,'getDeclaredConstructor')
+                or
+        ends-with(@Image,'setAccessible')
+        ])
+or
+(PrimaryPrefix/Name[
+        ends-with(@Image,'getDeclaredConstructor')
+        or
+        ends-with(@Image,'getDeclaredConstructors')
+        or
+        starts-with(@Image,'AccessibleObject.setAccessible')
+        ])
+)
+and
+(//ImportDeclaration/Name[
+        contains(@Image,'java.security.PrivilegedAction')])
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+
+public class Violation {
+  public void invalidCallsInMethod() throws SecurityException, NoSuchMethodException {
+    // Possible call to forbidden getDeclaredConstructors
+    Class[] arrayOfClass = new Class[1];
+    this.getClass().getDeclaredConstructors();
+    this.getClass().getDeclaredConstructor(arrayOfClass);
+    Class clazz = this.getClass();
+    clazz.getDeclaredConstructor(arrayOfClass);
+    clazz.getDeclaredConstructors();
+      // Possible call to forbidden setAccessible
+    clazz.getMethod("", arrayOfClass).setAccessible(false);
+    AccessibleObject.setAccessible(null, false);
+    Method.setAccessible(null, false);
+    Method[] methodsArray = clazz.getMethods();
+    int nbMethod;
+    for ( nbMethod = 0; nbMethod < methodsArray.length; nbMethod++ ) {
+      methodsArray[nbMethod].setAccessible(false);
+    }
+
+      // Possible call to forbidden PrivilegedAction
+    PrivilegedAction priv = (PrivilegedAction) new Object(); priv.run();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAssertAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using assert as an identifier; it became a reserved word in JDK 1.4"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidassertasidentifier">
+        <description>
+            Use of the term 'assert' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='assert']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String assert = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidBranchingStatementAsLastInLoop"
+          language="java"
+          since="5.0"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidBranchingStatementAsLastInLoopRule"
+          message="Avoid using a branching statement as the last in a loop."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidbranchingstatementaslastinloop">
+        <description>
+            Using a branching statement as the last part of a loop may be a bug, and/or is confusing.
+            Ensure that the usage is not a bug, or consider using another approach.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// unusual use of branching statement in a loop
+for (int i = 0; i < 10; i++) {
+    if (i*i <= 25) {
+        continue;
+    }
+    break;
+}
+
+// this makes more sense...
+for (int i = 0; i < 10; i++) {
+    if (i*i > 25) {
+        break;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCallingFinalize"
+          language="java"
+          since="3.0"
+          message="Avoid calling finalize() explicitly"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCallingFinalizeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcallingfinalize">
+        <description>
+            The method Object.finalize() is called by the garbage collector on an object when garbage collection determines
+            that there are no more references to the object. It should not be invoked by application logic.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+void foo() {
+    Bar b = new Bar();
+    b.finalize();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingNPE"

Review comment:
       This rule is enabled in our repo

##########
File path: check-rules/errorprone.xml
##########
@@ -0,0 +1,3721 @@
+<?xml version="1.0"?>
+
+<ruleset name="Error Prone"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+    <description>
+        Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
+    </description>
+
+    <rule name="AssignmentInOperand"
+          language="java"
+          since="1.03"
+          message="Avoid assignments in operands"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentInOperandRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmentinoperand">
+        <description>
+            Avoid assignments in operands; this can make code more complicated and harder to read.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    if ((x = getX()) == 3) {
+      System.out.println("3!");
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AssignmentToNonFinalStatic"
+          language="java"
+          since="2.2"
+          message="Possible unsafe assignment to a non-final static field in a constructor."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentToNonFinalStaticRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmenttononfinalstatic">
+        <description>
+            Identifies a possible unsafe usage of a static field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class StaticField {
+   static int x;
+   public FinalFields(int y) {
+    x = y; // unsafe
+   }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAccessibilityAlteration"
+          language="java"
+          since="4.1"
+          message="You should not modify visibility of class or methods using getDeclaredConstructors(), getDeclaredConstructor(Class[]), setAccessible() or PrivilegedAction."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidaccessibilityalteration">
+        <description>
+            Methods such as getDeclaredConstructors(), getDeclaredConstructor(Class[]) and setAccessible(),
+            as the interface PrivilegedAction, allow for the runtime alteration of variable, class, or
+            method visibility, even if they are private. This violates the principle of encapsulation.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimaryExpression[
+(
+(PrimarySuffix[
+        ends-with(@Image,'getDeclaredConstructors')
+                or
+        ends-with(@Image,'getDeclaredConstructor')
+                or
+        ends-with(@Image,'setAccessible')
+        ])
+or
+(PrimaryPrefix/Name[
+        ends-with(@Image,'getDeclaredConstructor')
+        or
+        ends-with(@Image,'getDeclaredConstructors')
+        or
+        starts-with(@Image,'AccessibleObject.setAccessible')
+        ])
+)
+and
+(//ImportDeclaration/Name[
+        contains(@Image,'java.security.PrivilegedAction')])
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+
+public class Violation {
+  public void invalidCallsInMethod() throws SecurityException, NoSuchMethodException {
+    // Possible call to forbidden getDeclaredConstructors
+    Class[] arrayOfClass = new Class[1];
+    this.getClass().getDeclaredConstructors();
+    this.getClass().getDeclaredConstructor(arrayOfClass);
+    Class clazz = this.getClass();
+    clazz.getDeclaredConstructor(arrayOfClass);
+    clazz.getDeclaredConstructors();
+      // Possible call to forbidden setAccessible
+    clazz.getMethod("", arrayOfClass).setAccessible(false);
+    AccessibleObject.setAccessible(null, false);
+    Method.setAccessible(null, false);
+    Method[] methodsArray = clazz.getMethods();
+    int nbMethod;
+    for ( nbMethod = 0; nbMethod < methodsArray.length; nbMethod++ ) {
+      methodsArray[nbMethod].setAccessible(false);
+    }
+
+      // Possible call to forbidden PrivilegedAction
+    PrivilegedAction priv = (PrivilegedAction) new Object(); priv.run();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAssertAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using assert as an identifier; it became a reserved word in JDK 1.4"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidassertasidentifier">
+        <description>
+            Use of the term 'assert' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='assert']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String assert = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidBranchingStatementAsLastInLoop"
+          language="java"
+          since="5.0"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidBranchingStatementAsLastInLoopRule"
+          message="Avoid using a branching statement as the last in a loop."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidbranchingstatementaslastinloop">
+        <description>
+            Using a branching statement as the last part of a loop may be a bug, and/or is confusing.
+            Ensure that the usage is not a bug, or consider using another approach.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// unusual use of branching statement in a loop
+for (int i = 0; i < 10; i++) {
+    if (i*i <= 25) {
+        continue;
+    }
+    break;
+}
+
+// this makes more sense...
+for (int i = 0; i < 10; i++) {
+    if (i*i > 25) {
+        break;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCallingFinalize"
+          language="java"
+          since="3.0"
+          message="Avoid calling finalize() explicitly"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCallingFinalizeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcallingfinalize">
+        <description>
+            The method Object.finalize() is called by the garbage collector on an object when garbage collection determines
+            that there are no more references to the object. It should not be invoked by application logic.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+void foo() {
+    Bar b = new Bar();
+    b.finalize();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingNPE"
+          language="java"
+          since="1.8"
+          message="Avoid catching NullPointerException; consider removing the cause of the NPE."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingnpe">
+        <description>
+            Code should never throw NullPointerExceptions under normal circumstances.  A catch block may hide the
+            original error, causing other, more subtle problems later on.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter/Type
+ /ReferenceType/ClassOrInterfaceType[@Image='NullPointerException']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    void bar() {
+        try {
+            // do something
+        } catch (NullPointerException npe) {
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingThrowable"
+          language="java"
+          since="1.2"
+          message="A catch statement should never catch throwable since it includes errors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCatchingThrowableRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingthrowable">
+        <description>
+            Catching Throwable errors is not recommended since its scope is very broad. It includes runtime issues such as
+            OutOfMemoryError that should be exposed and managed separately.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (Throwable th) {  // should not catch Throwable
+        th.printStackTrace();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDecimalLiteralsInBigDecimalConstructor"
+          language="java"
+          since="3.4"
+          message="Avoid creating BigDecimal with a decimal (float/double) literal. Use a String literal"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoiddecimalliteralsinbigdecimalconstructor">
+        <description>
+            One might assume that the result of "new BigDecimal(0.1)" is exactly equal to 0.1, but it is actually
+            equal to .1000000000000000055511151231257827021181583404541015625.
+            This is because 0.1 cannot be represented exactly as a double (or as a binary fraction of any finite
+            length). Thus, the long value that is being passed in to the constructor is not exactly equal to 0.1,
+            appearances notwithstanding.
+
+            The (String) constructor, on the other hand, is perfectly predictable: 'new BigDecimal("0.1")' is
+            exactly equal to 0.1, as one would expect.  Therefore, it is generally recommended that the
+            (String) constructor be used in preference to this one.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//AllocationExpression[pmd-java:typeIs('java.math.BigDecimal')]
+[Arguments/ArgumentList/Expression/PrimaryExpression
+    [
+        pmd-java:typeIs('float') or
+        pmd-java:typeIs('java.lang.Float') or
+        pmd-java:typeIs('double') or
+        pmd-java:typeIs('java.lang.Double')
+    ]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+BigDecimal bd = new BigDecimal(1.123);       // loss of precision, this would trigger the rule
+
+BigDecimal bd = new BigDecimal("1.123");     // preferred approach
+
+BigDecimal bd = new BigDecimal(12);          // preferred approach, ok for integer values
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDuplicateLiterals"
+          language="java"
+          since="1.0"
+          message="The String literal {0} appears {1} times in this file; the first occurrence is on line {2}"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidDuplicateLiteralsRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidduplicateliterals">
+        <description>
+            Code containing duplicate String literals can usually be improved by declaring the String as a constant field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private void bar() {
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+}
+private void buz(String x) {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidEnumAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using enum as an identifier; it's a reserved word in JDK 1.5"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidenumasidentifier">
+        <description>
+            Use of the term 'enum' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='enum']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String enum = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingMethodName"
+          language="java"
+          since="3.0"
+          message="Field {0} has the same name as a method"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingMethodNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingmethodname">
+        <description>
+            It can be confusing to have a field name with the same name as a method. While this is permitted,
+            having information (field) and actions (method) is not clear naming. Developers versed in
+            Smalltalk often prefer this approach as the methods denote accessor methods.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+    Object bar;
+    // bar is data or an action or both?
+    void bar() {
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingTypeName"
+          language="java"
+          since="3.0"
+          message="It is somewhat confusing to have a field name matching the declaring class name"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingTypeNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingtypename">
+        <description>
+            It is somewhat confusing to have a field name matching the declaring type name.
+            This probably means that type and/or field names should be chosen more carefully.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo extends Bar {
+    int foo;    // There is probably a better name that can be used
+}
+public interface Operation {
+    int OPERATION = 1; // There is probably a better name that can be used
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidInstanceofChecksInCatchClause"
+          language="java"
+          since="3.0"
+          message="An instanceof check is being performed on the caught exception.  Create a separate catch clause for this exception type."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidinstanceofchecksincatchclause">
+        <description>
+            Each caught exception type should be handled in its own catch clause.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter
+ /following-sibling::Block//InstanceOfExpression/PrimaryExpression/PrimaryPrefix
+  /Name[
+   @Image = ./ancestor::Block/preceding-sibling::FormalParameter
+    /VariableDeclaratorId/@Name
+  ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+try { // Avoid this
+    // do something
+} catch (Exception ee) {
+    if (ee instanceof IOException) {
+        cleanup();
+    }
+}
+
+try {  // Prefer this:
+    // do something
+} catch (IOException ee) {
+    cleanup();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLiteralsInIfCondition"
+          language="java"
+          since="4.2.6"
+          message="Avoid using Literals in Conditional Statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidliteralsinifcondition">
+        <description>
+            Avoid using hard-coded literals in conditional statements. By declaring them as static variables
+            or private members with descriptive names maintainability is enhanced. By default, the literals "-1" and "0" are ignored.
+            More exceptions can be defined with the property "ignoreMagicNumbers".
+
+            The rule doesn't consider deeper expressions by default, but this can be enabled via the property `ignoreExpressions`.
+            With this property set to false, if-conditions like `i == 1 + 5` are reported as well. Note that in that case,
+            the property ignoreMagicNumbers is not taken into account, if there are multiple literals involved in such an expression.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="ignoreMagicNumbers"
+                      description="Comma-separated list of magic numbers, that should be ignored"
+                      type="String" value="-1,0"/>
+            <property name="ignoreExpressions"
+                      description="If true, only literals in simple if conditions are considered. Otherwise literals in expressions are checked, too."
+                      type="Boolean" value="true"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(: simple case - no deep expressions :)
+//IfStatement[$ignoreExpressions = true()]/Expression/*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider also deeper expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression//*[local-name() != 'UnaryExpression' or @Operator != '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider negative literals :)
+//IfStatement[$ignoreExpressions = false()]/Expression//UnaryExpression[@Operator = '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), concat('-', @Image)))]
+|
+(: consider multiple literals in expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression[count(*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]) > 1]
+]]>
+                </value>
+            </property>
+            <property name="version" value="2.0"/>
+        </properties>
+        <example>
+            <![CDATA[
+private static final int MAX_NUMBER_OF_REQUESTS = 10;
+
+public void checkRequests() {
+
+    if (i == 10) {                        // magic number, buried in a method
+      doSomething();
+    }
+
+    if (i == MAX_NUMBER_OF_REQUESTS) {    // preferred approach
+      doSomething();
+    }
+
+    if (aString.indexOf('.') != -1) {}     // magic number -1, by default ignored
+    if (aString.indexOf('.') >= 0) { }     // alternative approach
+
+    if (aDouble > 0.0) {}                  // magic number 0.0
+    if (aDouble >= Double.MIN_VALUE) {}    // preferred approach
+
+    // with rule property "ignoreExpressions" set to "false"
+    if (i == pos + 5) {}  // violation: magic number 5 within an (additive) expression
+    if (i == pos + SUFFIX_LENGTH) {} // preferred approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLosingExceptionInformation"
+          since="4.2.6"
+          language="java"
+          message="Avoid statements in a catch block that invoke accessors on the exception without using the information"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidlosingexceptioninformation">
+        <description>
+            Statements in a catch block that invoke accessors on the exception without using the information
+            only add to code size.  Either remove the invocation, or use the return result.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/Block/BlockStatement/Statement/StatementExpression/PrimaryExpression/PrimaryPrefix/Name
+[
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getLocalizedMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getCause')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getStackTrace')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.toString')
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (SomeException se) {
+        se.getMessage();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidMultipleUnaryOperators"
+          language="java"
+          since="4.2"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidMultipleUnaryOperatorsRule"
+          message="Using multiple unary operators may be a bug, and/or is confusing."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidmultipleunaryoperators">
+        <description>
+            The use of multiple unary operators may be problematic, and/or confusing.
+            Ensure that the intended usage is not a bug, or consider simplifying the expression.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// These are typo bugs, or at best needlessly complex and confusing:
+int i = - -1;
+int j = + - +1;
+int z = ~~2;
+boolean b = !!true;
+boolean c = !!!true;
+
+// These are better:
+int i = 1;
+int j = -1;
+int z = 2;
+boolean b = true;
+boolean c = false;
+
+// And these just make your brain hurt:
+int i = ~-2;
+int j = -~7;
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidUsingOctalValues"
+          language="java"
+          since="3.9"
+          message="Do not start a literal by 0 unless it's an octal value"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidUsingOctalValuesRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidusingoctalvalues">
+        <description>
+            Integer literals should not start with zero since this denotes that the rest of literal will be
+            interpreted as an octal value.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+int i = 012;    // set i with 10 not 12
+int j = 010;    // set j with 8 not 10
+k = i * j;      // set k with 80 not 120
+]]>
+        </example>
+    </rule>
+
+    <rule name="BadComparison" ref="ComparisonWithNaN" deprecated="true" />
+
+    <rule name="BeanMembersShouldSerialize"
+          language="java"
+          since="1.1"
+          message="Found non-transient, non-static member. Please mark as transient or provide accessors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BeanMembersShouldSerializeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#beanmembersshouldserialize">
+        <description>
+            If a class is a bean, or is referenced by a bean directly or indirectly it needs to be serializable.
+            Member variables need to be marked as transient, static, or have accessor methods in the class. Marking
+            variables as transient is the safest and easiest modification. Accessor methods should follow the Java
+            naming conventions, i.e. for a variable named foo, getFoo() and setFoo() accessor methods should be provided.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private transient int someFoo;  // good, it's transient
+private static int otherFoo;    // also OK
+private int moreFoo;            // OK, has proper accessors, see below
+private int badFoo;             // bad, should be marked transient
+
+private void setMoreFoo(int moreFoo){
+      this.moreFoo = moreFoo;
+}
+
+private int getMoreFoo(){
+      return this.moreFoo;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="BrokenNullCheck"
+          language="java"
+          since="3.8"
+          message="Method call on object which may be null"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BrokenNullCheckRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#brokennullcheck">
+        <description>
+            The null check is broken since it will throw a NullPointerException itself.
+            It is likely that you used || instead of &amp;&amp; or vice versa.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+public String bar(String string) {
+  // should be &&
+    if (string!=null || !string.equals(""))
+        return string;
+  // should be ||
+    if (string==null && string.equals(""))
+        return string;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperFirst"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the start of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperfirst">
+        <description>Super should be called at the start of the method</description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='onCreate' or
+  @Name='onConfigurationChanged' or
+  @Name='onPostCreate' or
+  @Name='onPostResume' or
+  @Name='onRestart' or
+  @Name='onRestoreInstanceState' or
+  @Name='onResume' or
+  @Name='onStart'
+  ]
+    /Block[not(
+      (BlockStatement[1]/Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name]))]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onCreate(Bundle bundle) {
+        // missing call to super.onCreate(bundle)
+        foo();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperLast"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the end of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperlast">
+        <description>
+            Super should be called at the end of the method
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='finish' or
+  @Name='onDestroy' or
+  @Name='onPause' or
+  @Name='onSaveInstanceState' or
+  @Name='onStop' or
+  @Name='onTerminate'
+  ]
+   /Block/BlockStatement[last()]
+    [not(Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name])]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onPause() {
+        foo();
+        // missing call to super.onPause()
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CheckSkipResult"
+          language="java"
+          since="5.0"
+          message="Check the value returned by the skip() method of an InputStream to see if the requested number of bytes has been skipped."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CheckSkipResultRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#checkskipresult">
+        <description>
+            The skip() method may skip a smaller number of bytes than requested. Check the returned value to find out if it was the case or not.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private FileInputStream _s = new FileInputStream("file");
+
+   public void skip(int n) throws IOException {
+      _s.skip(n); // You are not sure that exactly n bytes are skipped
+   }
+
+   public void skipExactly(int n) throws IOException {
+      while (n != 0) {
+         long skipped = _s.skip(n);
+         if (skipped == 0)
+            throw new EOFException();
+         n -= skipped;
+      }
+   }
+]]>
+        </example>
+    </rule>
+
+    <rule name="ClassCastExceptionWithToArray"
+          language="java"
+          since="3.4"
+          message="This usage of the Collection.toArray() method will throw a ClassCastException."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#classcastexceptionwithtoarray">
+        <description>
+            When deriving an array of a specific class from your Collection, one should provide an array of
+            the same class as the parameter of the toArray() method. Doing otherwise you will will result
+            in a ClassCastException.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CastExpression[Type/ReferenceType/ClassOrInterfaceType[@Image != "Object"]]
+    /PrimaryExpression
+    [PrimaryPrefix/Name[ends-with(@Image, '.toArray')]]
+    [PrimarySuffix/Arguments[not(*)]]
+    [count(PrimarySuffix) = 1]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+Collection c = new ArrayList();
+Integer obj = new Integer(1);
+c.add(obj);
+
+    // this would trigger the rule (and throw a ClassCastException if executed)
+Integer[] a = (Integer [])c.toArray();
+
+   // this is fine and will not trigger the rule
+Integer[] b = (Integer [])c.toArray(new Integer[c.size()]);
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustBePublic"
+          language="java"
+          since="5.4.0"
+          message="clone() method must be public if the class implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustbepublic">
+        <description>
+            The java Manual says "By convention, classes that implement this interface should override
+            Object.clone (which is protected) with a public method."
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Public= false()]
+  [@Name = 'clone']
+  [@Arity = 0]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() throws CloneNotSupportedException { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    protected Foo clone() { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Object clone() // Ok
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustImplementCloneable"
+          language="java"
+          since="1.9"
+          message="clone() method should be implemented only if implementing Cloneable interface"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloneMethodMustImplementCloneableRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustimplementcloneable">
+        <description>
+            The method clone() should only be implemented if the class implements the Cloneable interface with the exception of
+            a final method that only throws CloneNotSupportedException.
+
+            The rule can also detect, if the class implements or extends a Cloneable class.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class MyClass {
+ public Object clone() throws CloneNotSupportedException {
+  return foo;
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodReturnTypeMustMatchClassName"
+          language="java"
+          minimumLanguageVersion="1.5"
+          since="5.4.0"
+          message="The return type of the clone() method must be the class name when implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodreturntypemustmatchclassname">
+        <description>
+            If a class implements cloneable the return type of the method clone() must be the class name. That way, the caller
+            of the clone method doesn't need to cast the returned clone to the correct type.
+
+            Note: This is only possible with Java 1.5 or higher.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and not (ResultType//ClassOrInterfaceType/@Image = ancestor::ClassOrInterfaceDeclaration[1]/@SimpleName)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() { // Violation, Object must be Foo
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Foo clone() { //Ok
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneThrowsCloneNotSupportedException"
+          deprecated="true"
+          language="java"
+          since="1.9"
+          message="clone() method should throw CloneNotSupportedException"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonethrowsclonenotsupportedexception">
+        <description>
+            The method clone() should throw a CloneNotSupportedException.
+
+            This rule is deprecated since PMD 6.35.0 without replacement. The rule has no real value as
+            `CloneNotSupportedException` is a checked exception and therefore you need to deal with it while
+            implementing the `clone()` method. You either need to declare the exception or catch it. If you catch it,
+            then subclasses can't throw it themselves explicitly. However, `Object.clone()` will still throw this
+            exception if the `Cloneable` interface is not implemented.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and count(NameList/Name[contains
+(@Image,'CloneNotSupportedException')]) = 0
+]
+[
+../../../../ClassOrInterfaceDeclaration[@Final = false()]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyClass implements Cloneable{
+    public Object clone() { // will cause an error
+         MyClass clone = (MyClass)super.clone();
+         return clone;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloseResource"
+          language="java"
+          since="1.2.2"
+          message="Ensure that resources like this {0} object are closed after use"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloseResourceRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#closeresource">
+        <description>
+            Ensure that resources (like `java.sql.Connection`, `java.sql.Statement`, and `java.sql.ResultSet` objects
+            and any subtype of `java.lang.AutoCloseable`) are always closed after use.
+            Failing to do so might result in resource leaks.
+
+            Note: It suffices to configure the super type, e.g. `java.lang.AutoClosable`, so that this rule automatically triggers
+            on any subtype (e.g. `java.io.FileInputStream`). Additionally specifying `java.sql.Connection` helps in detecting
+            the types, if the type resolution / auxclasspath is not correctly setup.
+
+            Note: Since PMD 6.16.0 the default value for the property `types` contains `java.lang.AutoCloseable` and detects
+            now cases where the standard `java.io.*Stream` classes are involved. In order to restore the old behaviour,
+            just remove "AutoCloseable" from the types.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Bar {
+    public void withSQL() {
+        Connection c = pool.getConnection();
+        try {
+            // do stuff
+        } catch (SQLException ex) {
+           // handle exception
+        } finally {
+            // oops, should close the connection using 'close'!
+            // c.close();
+        }
+    }
+
+    public void withFile() {
+        InputStream file = new FileInputStream(new File("/tmp/foo"));
+        try {
+            int c = file.in();
+        } catch (IOException e) {
+            // handle exception
+        } finally {
+            // TODO: close file
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CompareObjectsWithEquals"
+          language="java"
+          since="3.2"
+          message="Use equals() to compare object references."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#compareobjectswithequals">
+        <description>
+            Use `equals()` to compare object references; avoid comparing them with `==`.
+
+            Since comparing objects with named constants is useful in some cases (eg, when
+            defining constants for sentinel values), the rule ignores comparisons against
+            fields with all-caps name (eg `this == SENTINEL`), which is a common naming
+            convention for constant fields.
+
+            You may allow some types to be compared by reference by listing the exceptions
+            in the `typesThatCompareByReference` property.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="typesThatCompareByReference" type="List[String]" delimiter="," description="List of canonical type names for which reference comparison is allowed.">
+                <value>java.lang.Enum,java.lang.Class</value>
+            </property>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EqualityExpression
+    [count(
+        PrimaryExpression[pmd-java:typeIs('java.lang.Object')]
+        [not(some $t in $typesThatCompareByReference satisfies pmd-java:typeIs($t))]
+       ) = 2
+    ]
+    [not(PrimaryExpression[PrimaryPrefix/@ThisModifier = true()]
+                          [not(PrimarySuffix)]
+                          [ancestor::MethodDeclaration[@Name = 'equals']])
+    ]
+    (: Is not a field access with an all-caps identifier :)
+    [not(PrimaryExpression[not(PrimarySuffix) and PrimaryPrefix/Name[upper-case(@Image)=@Image]
+     or PrimaryExpression/PrimarySuffix[last()][upper-case(@Image)=@Image]])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+class Foo {
+  boolean bar(String a, String b) {
+    return a == b;
+  }
+}
+
+]]>
+        </example>
+    </rule>
+
+    <rule name="ComparisonWithNaN"
+          language="java"
+          since="6.36.0"
+          message="Comparisons with NaN always return false"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+        <description><![CDATA[
+            Reports comparisons with double and float `NaN` (Not-a-Number) values.
+            These are [specified](https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.21.1)
+            to have unintuitive behavior: NaN is considered unequal to itself.
+            This means a check like `someDouble == Double.NaN` will always return
+            false, even if `someDouble` is really the NaN value. To test whether a
+            value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+            (or `Float.isNaN`). The `!=` operator should be treated similarly.
+            Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+            and will always evaluate to false.
+
+            This rule has been renamed from "BadComparison" with PMD 6.36.0.
+        ]]></description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+        </example>
+    </rule>
+
+
+    <rule name="ConstructorCallsOverridableMethod"
+          language="java"
+          since="1.04"
+          message="Overridable {0} called during object construction"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#constructorcallsoverridablemethod">
+        <description>
+            Calling overridable methods during construction poses a risk of invoking methods on an incompletely
+            constructed object and can be difficult to debug.
+            It may leave the sub-class unable to construct its superclass or forced to replicate the construction
+            process completely within itself, losing the ability to call super().  If the default constructor
+            contains a call to an overridable method, the subclass may be completely uninstantiable.   Note that
+            this includes method calls throughout the control flow graph - i.e., if a constructor Foo() calls a
+            private method bar() that calls a public method buz(), this denotes a problem.
+        </description>
+        <priority>1</priority>
+        <example>
+            <![CDATA[
+public class SeniorClass {
+  public SeniorClass(){
+      toString(); //may throw NullPointerException if overridden
+  }
+  public String toString(){
+    return "IAmSeniorClass";
+  }
+}
+public class JuniorClass extends SeniorClass {
+  private String name;
+  public JuniorClass(){
+    super(); //Automatic call leads to NullPointerException
+    name = "JuniorClass";
+  }
+  public String toString(){
+    return name.toUpperCase();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DataflowAnomalyAnalysis"
+          language="java"
+          since="3.9"
+          message="Found ''{0}''-anomaly for variable ''{1}'' (lines ''{2}''-''{3}'')."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DataflowAnomalyAnalysisRule"
+          dfa="true"
+          deprecated="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dataflowanomalyanalysis">
+        <description>The dataflow analysis tracks local definitions, undefinitions and references to variables on different paths on the data flow.
+            From those informations there can be found various problems.
+
+            1. DU - Anomaly: A recently defined variable is undefined. These anomalies may appear in normal source text.
+            2. DD - Anomaly: A recently defined variable is redefined. This is ominous but don't have to be a bug.
+
+            This rule is deprecated. Use {% rule "java/bestpractices/UnusedAssignment" %} in category bestpractices instead.
+        </description>
+        <priority>5</priority>
+        <example>
+            <![CDATA[
+public void foo() {
+  int buz = 5;
+  buz = 6; // redefinition of buz -> dd-anomaly
+  foo(buz);
+  buz = 2;
+} // buz is undefined when leaving scope -> du-anomaly
+]]>
+        </example>
+    </rule>
+
+    <rule name="DetachedTestCase"
+          language="java"
+          since="6.13.0"
+          message="Probable detached JUnit test case."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#detachedtestcase">
+        <description>
+            The method appears to be a test case since it has public or default visibility,
+            non-static access, no arguments, no return value, has no annotations, but is a
+            member of a class that has one or more JUnit test cases. If it is a utility
+            method, it should likely have private visibility. If it is an ignored test, it
+            should be annotated with @Test and @Ignore.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value><![CDATA[
+//ClassOrInterfaceBodyDeclaration
+[../ClassOrInterfaceBodyDeclaration/Annotation/*/Name
+        [pmd-java:typeIs('org.junit.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestFactory')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
+         or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')]
+]
+[not(Annotation)]
+[MethodDeclaration[(@Public = true() or @PackagePrivate = true()) and @Static = false() and
+        ResultType[@Void = true()] and
+        MethodDeclarator/FormalParameters[@Size = 0]
+    ]
+]
+]]></value>
+            </property>
+            <property name="version" value="2.0" />
+        </properties>
+        <example>
+            <![CDATA[
+public class MyTest {
+    @Test
+    public void someTest() {
+    }
+
+    // violation: Not annotated
+    public void someOtherTest () {
+    }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallGarbageCollectionExplicitly"
+          language="java"
+          since="4.2"
+          message="Do not explicitly trigger a garbage collection."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotcallgarbagecollectionexplicitly">
+        <description>
+            Calls to System.gc(), Runtime.getRuntime().gc(), and System.runFinalization() are not advised. Code should have the
+            same behavior whether the garbage collection is disabled using the option -Xdisableexplicitgc or not.
+            Moreover, "modern" jvms do a very good job handling garbage collections. If memory usage issues unrelated to memory
+            leaks develop within an application, it should be dealt with JVM options rather than within the code itself.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+(starts-with(@Image, 'System.') and
+(starts-with(@Image, 'System.gc') or
+starts-with(@Image, 'System.runFinalization'))) or
+(
+starts-with(@Image,'Runtime.getRuntime') and
+../../PrimarySuffix[ends-with(@Image,'gc')]
+)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class GCCall {
+    public GCCall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+
+    public explicitGCcall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallSystemExit" ref="category/java/errorprone.xml/DoNotTerminateVM" deprecated="true" />
+
+    <rule name="DoNotExtendJavaLangThrowable"
+          language="java"
+          since="6.0.0"
+          message="Exceptions should not extend java.lang.Throwable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotextendjavalangthrowable">
+        <description>
+            Extend Exception or RuntimeException instead of Throwable.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration/ExtendsList/ClassOrInterfaceType
+  [@Image="Throwable" or @Image="java.lang.Throwable"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo extends Throwable { }
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotHardCodeSDCard"
+          since="4.2.6"
+          language="java"
+          message="Do not hardcode /sdcard."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donothardcodesdcard">
+        <description>
+            Use Environment.getExternalStorageDirectory() instead of "/sdcard"
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Literal[starts-with(@Image,'"/sdcard')]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyActivity extends Activity {
+    protected void foo() {
+        String storageLocation = "/sdcard/mypackage";   // hard-coded, poor approach
+
+       storageLocation = Environment.getExternalStorageDirectory() + "/mypackage"; // preferred approach
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotTerminateVM"
+          language="java"
+          since="4.1"
+          message="System.exit() should not be used in J2EE/JEE apps"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotterminatevm">
+        <description>
+            Web applications should not call `System.exit()`, since only the web container or the
+            application server should stop the JVM. Otherwise a web application would terminate all other applications
+            running on the same application server.
+
+            This rule also checks for the equivalent calls `Runtime.getRuntime().exit()` and `Runtime.getRuntime().halt()`.
+
+            This rule was called *DoNotCallSystemExit* until PMD 6.29.0.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+    starts-with(@Image,'System.exit')
+    or
+    (starts-with(@Image,'Runtime.getRuntime') and ../../PrimarySuffix[ends-with(@Image,'exit') or ends-with(@Image,'halt')])
+][not(ancestor::MethodDeclaration[1][@Name="main" and @Static = true()])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    System.exit(0);                 // never call this when running in an application server!
+}
+public void foo() {
+    Runtime.getRuntime().exit(0);   // never stop the JVM manually, the container will do this.
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotThrowExceptionInFinally"
+          language="java"
+          since="4.2"
+          message="A throw statement in a finally block makes the control flow hard to understand."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotthrowexceptioninfinally">
+        <description>
+            Throwing exceptions within a 'finally' block is confusing since they may mask other exceptions
+            or code defects.
+            Note: This is a PMD implementation of the Lint4j rule "A throw in a finally block"
+        </description>
+        <priority>4</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//FinallyStatement[descendant::ThrowStatement]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            // Here do some stuff
+        } catch( Exception e) {
+            // Handling the issue
+        } finally {
+            // is this really a good idea ?
+            throw new Exception();
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontImportSun"
+          language="java"
+          since="1.5"
+          message="Avoid importing anything from the 'sun.*' packages"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DontImportSunRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontimportsun">
+        <description>
+            Avoid importing anything from the 'sun.*' packages.  These packages are not portable and are likely to change.
+        </description>
+        <priority>4</priority>
+        <example>
+            <![CDATA[
+import sun.misc.foo;
+public class Foo {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontUseFloatTypeForLoopIndices"
+          language="java"
+          since="4.3"
+          message="Don't use floating point for loop indices. If you must use floating point, use double."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontusefloattypeforloopindices">
+        <description>
+            Don't use floating point for loop indices. If you must use floating point, use double
+            unless you're certain that float provides enough precision and you have a compelling
+            performance need (space or time).
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ForStatement/ForInit/LocalVariableDeclaration
+/Type/PrimitiveType[@Image="float"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Count {
+  public static void main(String[] args) {
+    final int START = 2000000000;
+    int count = 0;
+    for (float f = START; f < START + 50; f++)
+      count++;
+      //Prints 0 because (float) START == (float) (START + 50).
+      System.out.println(count);
+      //The termination test misbehaves due to floating point granularity.
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyCatchBlock"
+          language="java"
+          since="0.1"
+          message="Avoid empty catch blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptycatchblock">
+        <description>
+            Empty Catch Block finds instances where an exception is caught, but nothing is done.
+            In most circumstances, this swallows an exception which should either be acted on
+            or reported.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement
+ [not(Block/BlockStatement)]
+ [$allowCommentedBlocks != true() or Block/@containsComment = false()]
+ [FormalParameter/Type/ReferenceType
+   /ClassOrInterfaceType[@Image != 'InterruptedException' and @Image != 'CloneNotSupportedException']
+ ]
+ [FormalParameter/VariableDeclaratorId[not(matches(@Name, $allowExceptionNameRegex))]]
+]]>
+                </value>
+            </property>
+            <property name="allowCommentedBlocks" type="Boolean" description="Empty blocks containing comments will be skipped" value="false"/>
+            <property name="allowExceptionNameRegex" type="String" description="Empty blocks catching exceptions with names matching this regular expression will be skipped" value="^(ignored|expected)$"/>
+        </properties>
+        <example>
+            <![CDATA[
+public void doSomething() {
+    try {
+        FileInputStream fis = new FileInputStream("/tmp/bugger");
+    } catch (IOException ioe) {
+        // not good
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinalizer"
+          language="java"
+          since="1.5"
+          message="Avoid empty finalize methods"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinalizer">
+        <description>
+            Empty finalize methods serve no purpose and should be removed. Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Name='finalize'][@Arity = 0]
+  /Block[not(*)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+   protected void finalize() {}
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinallyBlock"

Review comment:
       This rule is enabled in our repo

##########
File path: check-rules/errorprone.xml
##########
@@ -0,0 +1,3721 @@
+<?xml version="1.0"?>
+
+<ruleset name="Error Prone"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+    <description>
+        Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
+    </description>
+
+    <rule name="AssignmentInOperand"
+          language="java"
+          since="1.03"
+          message="Avoid assignments in operands"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentInOperandRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmentinoperand">
+        <description>
+            Avoid assignments in operands; this can make code more complicated and harder to read.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    if ((x = getX()) == 3) {
+      System.out.println("3!");
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AssignmentToNonFinalStatic"
+          language="java"
+          since="2.2"
+          message="Possible unsafe assignment to a non-final static field in a constructor."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentToNonFinalStaticRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmenttononfinalstatic">
+        <description>
+            Identifies a possible unsafe usage of a static field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class StaticField {
+   static int x;
+   public FinalFields(int y) {
+    x = y; // unsafe
+   }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAccessibilityAlteration"
+          language="java"
+          since="4.1"
+          message="You should not modify visibility of class or methods using getDeclaredConstructors(), getDeclaredConstructor(Class[]), setAccessible() or PrivilegedAction."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidaccessibilityalteration">
+        <description>
+            Methods such as getDeclaredConstructors(), getDeclaredConstructor(Class[]) and setAccessible(),
+            as the interface PrivilegedAction, allow for the runtime alteration of variable, class, or
+            method visibility, even if they are private. This violates the principle of encapsulation.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimaryExpression[
+(
+(PrimarySuffix[
+        ends-with(@Image,'getDeclaredConstructors')
+                or
+        ends-with(@Image,'getDeclaredConstructor')
+                or
+        ends-with(@Image,'setAccessible')
+        ])
+or
+(PrimaryPrefix/Name[
+        ends-with(@Image,'getDeclaredConstructor')
+        or
+        ends-with(@Image,'getDeclaredConstructors')
+        or
+        starts-with(@Image,'AccessibleObject.setAccessible')
+        ])
+)
+and
+(//ImportDeclaration/Name[
+        contains(@Image,'java.security.PrivilegedAction')])
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+
+public class Violation {
+  public void invalidCallsInMethod() throws SecurityException, NoSuchMethodException {
+    // Possible call to forbidden getDeclaredConstructors
+    Class[] arrayOfClass = new Class[1];
+    this.getClass().getDeclaredConstructors();
+    this.getClass().getDeclaredConstructor(arrayOfClass);
+    Class clazz = this.getClass();
+    clazz.getDeclaredConstructor(arrayOfClass);
+    clazz.getDeclaredConstructors();
+      // Possible call to forbidden setAccessible
+    clazz.getMethod("", arrayOfClass).setAccessible(false);
+    AccessibleObject.setAccessible(null, false);
+    Method.setAccessible(null, false);
+    Method[] methodsArray = clazz.getMethods();
+    int nbMethod;
+    for ( nbMethod = 0; nbMethod < methodsArray.length; nbMethod++ ) {
+      methodsArray[nbMethod].setAccessible(false);
+    }
+
+      // Possible call to forbidden PrivilegedAction
+    PrivilegedAction priv = (PrivilegedAction) new Object(); priv.run();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAssertAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using assert as an identifier; it became a reserved word in JDK 1.4"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidassertasidentifier">
+        <description>
+            Use of the term 'assert' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='assert']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String assert = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidBranchingStatementAsLastInLoop"
+          language="java"
+          since="5.0"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidBranchingStatementAsLastInLoopRule"
+          message="Avoid using a branching statement as the last in a loop."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidbranchingstatementaslastinloop">
+        <description>
+            Using a branching statement as the last part of a loop may be a bug, and/or is confusing.
+            Ensure that the usage is not a bug, or consider using another approach.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// unusual use of branching statement in a loop
+for (int i = 0; i < 10; i++) {
+    if (i*i <= 25) {
+        continue;
+    }
+    break;
+}
+
+// this makes more sense...
+for (int i = 0; i < 10; i++) {
+    if (i*i > 25) {
+        break;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCallingFinalize"
+          language="java"
+          since="3.0"
+          message="Avoid calling finalize() explicitly"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCallingFinalizeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcallingfinalize">
+        <description>
+            The method Object.finalize() is called by the garbage collector on an object when garbage collection determines
+            that there are no more references to the object. It should not be invoked by application logic.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+void foo() {
+    Bar b = new Bar();
+    b.finalize();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingNPE"
+          language="java"
+          since="1.8"
+          message="Avoid catching NullPointerException; consider removing the cause of the NPE."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingnpe">
+        <description>
+            Code should never throw NullPointerExceptions under normal circumstances.  A catch block may hide the
+            original error, causing other, more subtle problems later on.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter/Type
+ /ReferenceType/ClassOrInterfaceType[@Image='NullPointerException']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    void bar() {
+        try {
+            // do something
+        } catch (NullPointerException npe) {
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingThrowable"
+          language="java"
+          since="1.2"
+          message="A catch statement should never catch throwable since it includes errors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCatchingThrowableRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingthrowable">
+        <description>
+            Catching Throwable errors is not recommended since its scope is very broad. It includes runtime issues such as
+            OutOfMemoryError that should be exposed and managed separately.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (Throwable th) {  // should not catch Throwable
+        th.printStackTrace();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDecimalLiteralsInBigDecimalConstructor"
+          language="java"
+          since="3.4"
+          message="Avoid creating BigDecimal with a decimal (float/double) literal. Use a String literal"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoiddecimalliteralsinbigdecimalconstructor">
+        <description>
+            One might assume that the result of "new BigDecimal(0.1)" is exactly equal to 0.1, but it is actually
+            equal to .1000000000000000055511151231257827021181583404541015625.
+            This is because 0.1 cannot be represented exactly as a double (or as a binary fraction of any finite
+            length). Thus, the long value that is being passed in to the constructor is not exactly equal to 0.1,
+            appearances notwithstanding.
+
+            The (String) constructor, on the other hand, is perfectly predictable: 'new BigDecimal("0.1")' is
+            exactly equal to 0.1, as one would expect.  Therefore, it is generally recommended that the
+            (String) constructor be used in preference to this one.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//AllocationExpression[pmd-java:typeIs('java.math.BigDecimal')]
+[Arguments/ArgumentList/Expression/PrimaryExpression
+    [
+        pmd-java:typeIs('float') or
+        pmd-java:typeIs('java.lang.Float') or
+        pmd-java:typeIs('double') or
+        pmd-java:typeIs('java.lang.Double')
+    ]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+BigDecimal bd = new BigDecimal(1.123);       // loss of precision, this would trigger the rule
+
+BigDecimal bd = new BigDecimal("1.123");     // preferred approach
+
+BigDecimal bd = new BigDecimal(12);          // preferred approach, ok for integer values
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDuplicateLiterals"
+          language="java"
+          since="1.0"
+          message="The String literal {0} appears {1} times in this file; the first occurrence is on line {2}"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidDuplicateLiteralsRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidduplicateliterals">
+        <description>
+            Code containing duplicate String literals can usually be improved by declaring the String as a constant field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private void bar() {
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+}
+private void buz(String x) {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidEnumAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using enum as an identifier; it's a reserved word in JDK 1.5"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidenumasidentifier">
+        <description>
+            Use of the term 'enum' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='enum']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String enum = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingMethodName"
+          language="java"
+          since="3.0"
+          message="Field {0} has the same name as a method"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingMethodNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingmethodname">
+        <description>
+            It can be confusing to have a field name with the same name as a method. While this is permitted,
+            having information (field) and actions (method) is not clear naming. Developers versed in
+            Smalltalk often prefer this approach as the methods denote accessor methods.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+    Object bar;
+    // bar is data or an action or both?
+    void bar() {
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingTypeName"
+          language="java"
+          since="3.0"
+          message="It is somewhat confusing to have a field name matching the declaring class name"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingTypeNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingtypename">
+        <description>
+            It is somewhat confusing to have a field name matching the declaring type name.
+            This probably means that type and/or field names should be chosen more carefully.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo extends Bar {
+    int foo;    // There is probably a better name that can be used
+}
+public interface Operation {
+    int OPERATION = 1; // There is probably a better name that can be used
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidInstanceofChecksInCatchClause"
+          language="java"
+          since="3.0"
+          message="An instanceof check is being performed on the caught exception.  Create a separate catch clause for this exception type."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidinstanceofchecksincatchclause">
+        <description>
+            Each caught exception type should be handled in its own catch clause.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter
+ /following-sibling::Block//InstanceOfExpression/PrimaryExpression/PrimaryPrefix
+  /Name[
+   @Image = ./ancestor::Block/preceding-sibling::FormalParameter
+    /VariableDeclaratorId/@Name
+  ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+try { // Avoid this
+    // do something
+} catch (Exception ee) {
+    if (ee instanceof IOException) {
+        cleanup();
+    }
+}
+
+try {  // Prefer this:
+    // do something
+} catch (IOException ee) {
+    cleanup();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLiteralsInIfCondition"
+          language="java"
+          since="4.2.6"
+          message="Avoid using Literals in Conditional Statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidliteralsinifcondition">
+        <description>
+            Avoid using hard-coded literals in conditional statements. By declaring them as static variables
+            or private members with descriptive names maintainability is enhanced. By default, the literals "-1" and "0" are ignored.
+            More exceptions can be defined with the property "ignoreMagicNumbers".
+
+            The rule doesn't consider deeper expressions by default, but this can be enabled via the property `ignoreExpressions`.
+            With this property set to false, if-conditions like `i == 1 + 5` are reported as well. Note that in that case,
+            the property ignoreMagicNumbers is not taken into account, if there are multiple literals involved in such an expression.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="ignoreMagicNumbers"
+                      description="Comma-separated list of magic numbers, that should be ignored"
+                      type="String" value="-1,0"/>
+            <property name="ignoreExpressions"
+                      description="If true, only literals in simple if conditions are considered. Otherwise literals in expressions are checked, too."
+                      type="Boolean" value="true"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(: simple case - no deep expressions :)
+//IfStatement[$ignoreExpressions = true()]/Expression/*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider also deeper expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression//*[local-name() != 'UnaryExpression' or @Operator != '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider negative literals :)
+//IfStatement[$ignoreExpressions = false()]/Expression//UnaryExpression[@Operator = '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), concat('-', @Image)))]
+|
+(: consider multiple literals in expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression[count(*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]) > 1]
+]]>
+                </value>
+            </property>
+            <property name="version" value="2.0"/>
+        </properties>
+        <example>
+            <![CDATA[
+private static final int MAX_NUMBER_OF_REQUESTS = 10;
+
+public void checkRequests() {
+
+    if (i == 10) {                        // magic number, buried in a method
+      doSomething();
+    }
+
+    if (i == MAX_NUMBER_OF_REQUESTS) {    // preferred approach
+      doSomething();
+    }
+
+    if (aString.indexOf('.') != -1) {}     // magic number -1, by default ignored
+    if (aString.indexOf('.') >= 0) { }     // alternative approach
+
+    if (aDouble > 0.0) {}                  // magic number 0.0
+    if (aDouble >= Double.MIN_VALUE) {}    // preferred approach
+
+    // with rule property "ignoreExpressions" set to "false"
+    if (i == pos + 5) {}  // violation: magic number 5 within an (additive) expression
+    if (i == pos + SUFFIX_LENGTH) {} // preferred approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLosingExceptionInformation"
+          since="4.2.6"
+          language="java"
+          message="Avoid statements in a catch block that invoke accessors on the exception without using the information"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidlosingexceptioninformation">
+        <description>
+            Statements in a catch block that invoke accessors on the exception without using the information
+            only add to code size.  Either remove the invocation, or use the return result.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/Block/BlockStatement/Statement/StatementExpression/PrimaryExpression/PrimaryPrefix/Name
+[
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getLocalizedMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getCause')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getStackTrace')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.toString')
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (SomeException se) {
+        se.getMessage();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidMultipleUnaryOperators"
+          language="java"
+          since="4.2"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidMultipleUnaryOperatorsRule"
+          message="Using multiple unary operators may be a bug, and/or is confusing."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidmultipleunaryoperators">
+        <description>
+            The use of multiple unary operators may be problematic, and/or confusing.
+            Ensure that the intended usage is not a bug, or consider simplifying the expression.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// These are typo bugs, or at best needlessly complex and confusing:
+int i = - -1;
+int j = + - +1;
+int z = ~~2;
+boolean b = !!true;
+boolean c = !!!true;
+
+// These are better:
+int i = 1;
+int j = -1;
+int z = 2;
+boolean b = true;
+boolean c = false;
+
+// And these just make your brain hurt:
+int i = ~-2;
+int j = -~7;
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidUsingOctalValues"
+          language="java"
+          since="3.9"
+          message="Do not start a literal by 0 unless it's an octal value"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidUsingOctalValuesRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidusingoctalvalues">
+        <description>
+            Integer literals should not start with zero since this denotes that the rest of literal will be
+            interpreted as an octal value.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+int i = 012;    // set i with 10 not 12
+int j = 010;    // set j with 8 not 10
+k = i * j;      // set k with 80 not 120
+]]>
+        </example>
+    </rule>
+
+    <rule name="BadComparison" ref="ComparisonWithNaN" deprecated="true" />
+
+    <rule name="BeanMembersShouldSerialize"
+          language="java"
+          since="1.1"
+          message="Found non-transient, non-static member. Please mark as transient or provide accessors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BeanMembersShouldSerializeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#beanmembersshouldserialize">
+        <description>
+            If a class is a bean, or is referenced by a bean directly or indirectly it needs to be serializable.
+            Member variables need to be marked as transient, static, or have accessor methods in the class. Marking
+            variables as transient is the safest and easiest modification. Accessor methods should follow the Java
+            naming conventions, i.e. for a variable named foo, getFoo() and setFoo() accessor methods should be provided.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private transient int someFoo;  // good, it's transient
+private static int otherFoo;    // also OK
+private int moreFoo;            // OK, has proper accessors, see below
+private int badFoo;             // bad, should be marked transient
+
+private void setMoreFoo(int moreFoo){
+      this.moreFoo = moreFoo;
+}
+
+private int getMoreFoo(){
+      return this.moreFoo;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="BrokenNullCheck"
+          language="java"
+          since="3.8"
+          message="Method call on object which may be null"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BrokenNullCheckRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#brokennullcheck">
+        <description>
+            The null check is broken since it will throw a NullPointerException itself.
+            It is likely that you used || instead of &amp;&amp; or vice versa.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+public String bar(String string) {
+  // should be &&
+    if (string!=null || !string.equals(""))
+        return string;
+  // should be ||
+    if (string==null && string.equals(""))
+        return string;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperFirst"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the start of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperfirst">
+        <description>Super should be called at the start of the method</description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='onCreate' or
+  @Name='onConfigurationChanged' or
+  @Name='onPostCreate' or
+  @Name='onPostResume' or
+  @Name='onRestart' or
+  @Name='onRestoreInstanceState' or
+  @Name='onResume' or
+  @Name='onStart'
+  ]
+    /Block[not(
+      (BlockStatement[1]/Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name]))]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onCreate(Bundle bundle) {
+        // missing call to super.onCreate(bundle)
+        foo();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperLast"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the end of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperlast">
+        <description>
+            Super should be called at the end of the method
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='finish' or
+  @Name='onDestroy' or
+  @Name='onPause' or
+  @Name='onSaveInstanceState' or
+  @Name='onStop' or
+  @Name='onTerminate'
+  ]
+   /Block/BlockStatement[last()]
+    [not(Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name])]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onPause() {
+        foo();
+        // missing call to super.onPause()
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CheckSkipResult"
+          language="java"
+          since="5.0"
+          message="Check the value returned by the skip() method of an InputStream to see if the requested number of bytes has been skipped."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CheckSkipResultRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#checkskipresult">
+        <description>
+            The skip() method may skip a smaller number of bytes than requested. Check the returned value to find out if it was the case or not.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private FileInputStream _s = new FileInputStream("file");
+
+   public void skip(int n) throws IOException {
+      _s.skip(n); // You are not sure that exactly n bytes are skipped
+   }
+
+   public void skipExactly(int n) throws IOException {
+      while (n != 0) {
+         long skipped = _s.skip(n);
+         if (skipped == 0)
+            throw new EOFException();
+         n -= skipped;
+      }
+   }
+]]>
+        </example>
+    </rule>
+
+    <rule name="ClassCastExceptionWithToArray"
+          language="java"
+          since="3.4"
+          message="This usage of the Collection.toArray() method will throw a ClassCastException."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#classcastexceptionwithtoarray">
+        <description>
+            When deriving an array of a specific class from your Collection, one should provide an array of
+            the same class as the parameter of the toArray() method. Doing otherwise you will will result
+            in a ClassCastException.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CastExpression[Type/ReferenceType/ClassOrInterfaceType[@Image != "Object"]]
+    /PrimaryExpression
+    [PrimaryPrefix/Name[ends-with(@Image, '.toArray')]]
+    [PrimarySuffix/Arguments[not(*)]]
+    [count(PrimarySuffix) = 1]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+Collection c = new ArrayList();
+Integer obj = new Integer(1);
+c.add(obj);
+
+    // this would trigger the rule (and throw a ClassCastException if executed)
+Integer[] a = (Integer [])c.toArray();
+
+   // this is fine and will not trigger the rule
+Integer[] b = (Integer [])c.toArray(new Integer[c.size()]);
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustBePublic"
+          language="java"
+          since="5.4.0"
+          message="clone() method must be public if the class implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustbepublic">
+        <description>
+            The java Manual says "By convention, classes that implement this interface should override
+            Object.clone (which is protected) with a public method."
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Public= false()]
+  [@Name = 'clone']
+  [@Arity = 0]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() throws CloneNotSupportedException { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    protected Foo clone() { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Object clone() // Ok
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustImplementCloneable"
+          language="java"
+          since="1.9"
+          message="clone() method should be implemented only if implementing Cloneable interface"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloneMethodMustImplementCloneableRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustimplementcloneable">
+        <description>
+            The method clone() should only be implemented if the class implements the Cloneable interface with the exception of
+            a final method that only throws CloneNotSupportedException.
+
+            The rule can also detect, if the class implements or extends a Cloneable class.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class MyClass {
+ public Object clone() throws CloneNotSupportedException {
+  return foo;
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodReturnTypeMustMatchClassName"
+          language="java"
+          minimumLanguageVersion="1.5"
+          since="5.4.0"
+          message="The return type of the clone() method must be the class name when implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodreturntypemustmatchclassname">
+        <description>
+            If a class implements cloneable the return type of the method clone() must be the class name. That way, the caller
+            of the clone method doesn't need to cast the returned clone to the correct type.
+
+            Note: This is only possible with Java 1.5 or higher.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and not (ResultType//ClassOrInterfaceType/@Image = ancestor::ClassOrInterfaceDeclaration[1]/@SimpleName)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() { // Violation, Object must be Foo
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Foo clone() { //Ok
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneThrowsCloneNotSupportedException"
+          deprecated="true"
+          language="java"
+          since="1.9"
+          message="clone() method should throw CloneNotSupportedException"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonethrowsclonenotsupportedexception">
+        <description>
+            The method clone() should throw a CloneNotSupportedException.
+
+            This rule is deprecated since PMD 6.35.0 without replacement. The rule has no real value as
+            `CloneNotSupportedException` is a checked exception and therefore you need to deal with it while
+            implementing the `clone()` method. You either need to declare the exception or catch it. If you catch it,
+            then subclasses can't throw it themselves explicitly. However, `Object.clone()` will still throw this
+            exception if the `Cloneable` interface is not implemented.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and count(NameList/Name[contains
+(@Image,'CloneNotSupportedException')]) = 0
+]
+[
+../../../../ClassOrInterfaceDeclaration[@Final = false()]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyClass implements Cloneable{
+    public Object clone() { // will cause an error
+         MyClass clone = (MyClass)super.clone();
+         return clone;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloseResource"
+          language="java"
+          since="1.2.2"
+          message="Ensure that resources like this {0} object are closed after use"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloseResourceRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#closeresource">
+        <description>
+            Ensure that resources (like `java.sql.Connection`, `java.sql.Statement`, and `java.sql.ResultSet` objects
+            and any subtype of `java.lang.AutoCloseable`) are always closed after use.
+            Failing to do so might result in resource leaks.
+
+            Note: It suffices to configure the super type, e.g. `java.lang.AutoClosable`, so that this rule automatically triggers
+            on any subtype (e.g. `java.io.FileInputStream`). Additionally specifying `java.sql.Connection` helps in detecting
+            the types, if the type resolution / auxclasspath is not correctly setup.
+
+            Note: Since PMD 6.16.0 the default value for the property `types` contains `java.lang.AutoCloseable` and detects
+            now cases where the standard `java.io.*Stream` classes are involved. In order to restore the old behaviour,
+            just remove "AutoCloseable" from the types.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Bar {
+    public void withSQL() {
+        Connection c = pool.getConnection();
+        try {
+            // do stuff
+        } catch (SQLException ex) {
+           // handle exception
+        } finally {
+            // oops, should close the connection using 'close'!
+            // c.close();
+        }
+    }
+
+    public void withFile() {
+        InputStream file = new FileInputStream(new File("/tmp/foo"));
+        try {
+            int c = file.in();
+        } catch (IOException e) {
+            // handle exception
+        } finally {
+            // TODO: close file
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CompareObjectsWithEquals"
+          language="java"
+          since="3.2"
+          message="Use equals() to compare object references."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#compareobjectswithequals">
+        <description>
+            Use `equals()` to compare object references; avoid comparing them with `==`.
+
+            Since comparing objects with named constants is useful in some cases (eg, when
+            defining constants for sentinel values), the rule ignores comparisons against
+            fields with all-caps name (eg `this == SENTINEL`), which is a common naming
+            convention for constant fields.
+
+            You may allow some types to be compared by reference by listing the exceptions
+            in the `typesThatCompareByReference` property.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="typesThatCompareByReference" type="List[String]" delimiter="," description="List of canonical type names for which reference comparison is allowed.">
+                <value>java.lang.Enum,java.lang.Class</value>
+            </property>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EqualityExpression
+    [count(
+        PrimaryExpression[pmd-java:typeIs('java.lang.Object')]
+        [not(some $t in $typesThatCompareByReference satisfies pmd-java:typeIs($t))]
+       ) = 2
+    ]
+    [not(PrimaryExpression[PrimaryPrefix/@ThisModifier = true()]
+                          [not(PrimarySuffix)]
+                          [ancestor::MethodDeclaration[@Name = 'equals']])
+    ]
+    (: Is not a field access with an all-caps identifier :)
+    [not(PrimaryExpression[not(PrimarySuffix) and PrimaryPrefix/Name[upper-case(@Image)=@Image]
+     or PrimaryExpression/PrimarySuffix[last()][upper-case(@Image)=@Image]])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+class Foo {
+  boolean bar(String a, String b) {
+    return a == b;
+  }
+}
+
+]]>
+        </example>
+    </rule>
+
+    <rule name="ComparisonWithNaN"
+          language="java"
+          since="6.36.0"
+          message="Comparisons with NaN always return false"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+        <description><![CDATA[
+            Reports comparisons with double and float `NaN` (Not-a-Number) values.
+            These are [specified](https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.21.1)
+            to have unintuitive behavior: NaN is considered unequal to itself.
+            This means a check like `someDouble == Double.NaN` will always return
+            false, even if `someDouble` is really the NaN value. To test whether a
+            value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+            (or `Float.isNaN`). The `!=` operator should be treated similarly.
+            Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+            and will always evaluate to false.
+
+            This rule has been renamed from "BadComparison" with PMD 6.36.0.
+        ]]></description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+        </example>
+    </rule>
+
+
+    <rule name="ConstructorCallsOverridableMethod"
+          language="java"
+          since="1.04"
+          message="Overridable {0} called during object construction"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#constructorcallsoverridablemethod">
+        <description>
+            Calling overridable methods during construction poses a risk of invoking methods on an incompletely
+            constructed object and can be difficult to debug.
+            It may leave the sub-class unable to construct its superclass or forced to replicate the construction
+            process completely within itself, losing the ability to call super().  If the default constructor
+            contains a call to an overridable method, the subclass may be completely uninstantiable.   Note that
+            this includes method calls throughout the control flow graph - i.e., if a constructor Foo() calls a
+            private method bar() that calls a public method buz(), this denotes a problem.
+        </description>
+        <priority>1</priority>
+        <example>
+            <![CDATA[
+public class SeniorClass {
+  public SeniorClass(){
+      toString(); //may throw NullPointerException if overridden
+  }
+  public String toString(){
+    return "IAmSeniorClass";
+  }
+}
+public class JuniorClass extends SeniorClass {
+  private String name;
+  public JuniorClass(){
+    super(); //Automatic call leads to NullPointerException
+    name = "JuniorClass";
+  }
+  public String toString(){
+    return name.toUpperCase();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DataflowAnomalyAnalysis"
+          language="java"
+          since="3.9"
+          message="Found ''{0}''-anomaly for variable ''{1}'' (lines ''{2}''-''{3}'')."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DataflowAnomalyAnalysisRule"
+          dfa="true"
+          deprecated="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dataflowanomalyanalysis">
+        <description>The dataflow analysis tracks local definitions, undefinitions and references to variables on different paths on the data flow.
+            From those informations there can be found various problems.
+
+            1. DU - Anomaly: A recently defined variable is undefined. These anomalies may appear in normal source text.
+            2. DD - Anomaly: A recently defined variable is redefined. This is ominous but don't have to be a bug.
+
+            This rule is deprecated. Use {% rule "java/bestpractices/UnusedAssignment" %} in category bestpractices instead.
+        </description>
+        <priority>5</priority>
+        <example>
+            <![CDATA[
+public void foo() {
+  int buz = 5;
+  buz = 6; // redefinition of buz -> dd-anomaly
+  foo(buz);
+  buz = 2;
+} // buz is undefined when leaving scope -> du-anomaly
+]]>
+        </example>
+    </rule>
+
+    <rule name="DetachedTestCase"
+          language="java"
+          since="6.13.0"
+          message="Probable detached JUnit test case."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#detachedtestcase">
+        <description>
+            The method appears to be a test case since it has public or default visibility,
+            non-static access, no arguments, no return value, has no annotations, but is a
+            member of a class that has one or more JUnit test cases. If it is a utility
+            method, it should likely have private visibility. If it is an ignored test, it
+            should be annotated with @Test and @Ignore.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value><![CDATA[
+//ClassOrInterfaceBodyDeclaration
+[../ClassOrInterfaceBodyDeclaration/Annotation/*/Name
+        [pmd-java:typeIs('org.junit.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestFactory')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
+         or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')]
+]
+[not(Annotation)]
+[MethodDeclaration[(@Public = true() or @PackagePrivate = true()) and @Static = false() and
+        ResultType[@Void = true()] and
+        MethodDeclarator/FormalParameters[@Size = 0]
+    ]
+]
+]]></value>
+            </property>
+            <property name="version" value="2.0" />
+        </properties>
+        <example>
+            <![CDATA[
+public class MyTest {
+    @Test
+    public void someTest() {
+    }
+
+    // violation: Not annotated
+    public void someOtherTest () {
+    }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallGarbageCollectionExplicitly"
+          language="java"
+          since="4.2"
+          message="Do not explicitly trigger a garbage collection."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotcallgarbagecollectionexplicitly">
+        <description>
+            Calls to System.gc(), Runtime.getRuntime().gc(), and System.runFinalization() are not advised. Code should have the
+            same behavior whether the garbage collection is disabled using the option -Xdisableexplicitgc or not.
+            Moreover, "modern" jvms do a very good job handling garbage collections. If memory usage issues unrelated to memory
+            leaks develop within an application, it should be dealt with JVM options rather than within the code itself.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+(starts-with(@Image, 'System.') and
+(starts-with(@Image, 'System.gc') or
+starts-with(@Image, 'System.runFinalization'))) or
+(
+starts-with(@Image,'Runtime.getRuntime') and
+../../PrimarySuffix[ends-with(@Image,'gc')]
+)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class GCCall {
+    public GCCall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+
+    public explicitGCcall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallSystemExit" ref="category/java/errorprone.xml/DoNotTerminateVM" deprecated="true" />
+
+    <rule name="DoNotExtendJavaLangThrowable"
+          language="java"
+          since="6.0.0"
+          message="Exceptions should not extend java.lang.Throwable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotextendjavalangthrowable">
+        <description>
+            Extend Exception or RuntimeException instead of Throwable.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration/ExtendsList/ClassOrInterfaceType
+  [@Image="Throwable" or @Image="java.lang.Throwable"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo extends Throwable { }
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotHardCodeSDCard"
+          since="4.2.6"
+          language="java"
+          message="Do not hardcode /sdcard."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donothardcodesdcard">
+        <description>
+            Use Environment.getExternalStorageDirectory() instead of "/sdcard"
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Literal[starts-with(@Image,'"/sdcard')]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyActivity extends Activity {
+    protected void foo() {
+        String storageLocation = "/sdcard/mypackage";   // hard-coded, poor approach
+
+       storageLocation = Environment.getExternalStorageDirectory() + "/mypackage"; // preferred approach
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotTerminateVM"
+          language="java"
+          since="4.1"
+          message="System.exit() should not be used in J2EE/JEE apps"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotterminatevm">
+        <description>
+            Web applications should not call `System.exit()`, since only the web container or the
+            application server should stop the JVM. Otherwise a web application would terminate all other applications
+            running on the same application server.
+
+            This rule also checks for the equivalent calls `Runtime.getRuntime().exit()` and `Runtime.getRuntime().halt()`.
+
+            This rule was called *DoNotCallSystemExit* until PMD 6.29.0.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+    starts-with(@Image,'System.exit')
+    or
+    (starts-with(@Image,'Runtime.getRuntime') and ../../PrimarySuffix[ends-with(@Image,'exit') or ends-with(@Image,'halt')])
+][not(ancestor::MethodDeclaration[1][@Name="main" and @Static = true()])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    System.exit(0);                 // never call this when running in an application server!
+}
+public void foo() {
+    Runtime.getRuntime().exit(0);   // never stop the JVM manually, the container will do this.
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotThrowExceptionInFinally"
+          language="java"
+          since="4.2"
+          message="A throw statement in a finally block makes the control flow hard to understand."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotthrowexceptioninfinally">
+        <description>
+            Throwing exceptions within a 'finally' block is confusing since they may mask other exceptions
+            or code defects.
+            Note: This is a PMD implementation of the Lint4j rule "A throw in a finally block"
+        </description>
+        <priority>4</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//FinallyStatement[descendant::ThrowStatement]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            // Here do some stuff
+        } catch( Exception e) {
+            // Handling the issue
+        } finally {
+            // is this really a good idea ?
+            throw new Exception();
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontImportSun"
+          language="java"
+          since="1.5"
+          message="Avoid importing anything from the 'sun.*' packages"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DontImportSunRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontimportsun">
+        <description>
+            Avoid importing anything from the 'sun.*' packages.  These packages are not portable and are likely to change.
+        </description>
+        <priority>4</priority>
+        <example>
+            <![CDATA[
+import sun.misc.foo;
+public class Foo {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontUseFloatTypeForLoopIndices"
+          language="java"
+          since="4.3"
+          message="Don't use floating point for loop indices. If you must use floating point, use double."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontusefloattypeforloopindices">
+        <description>
+            Don't use floating point for loop indices. If you must use floating point, use double
+            unless you're certain that float provides enough precision and you have a compelling
+            performance need (space or time).
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ForStatement/ForInit/LocalVariableDeclaration
+/Type/PrimitiveType[@Image="float"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Count {
+  public static void main(String[] args) {
+    final int START = 2000000000;
+    int count = 0;
+    for (float f = START; f < START + 50; f++)
+      count++;
+      //Prints 0 because (float) START == (float) (START + 50).
+      System.out.println(count);
+      //The termination test misbehaves due to floating point granularity.
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyCatchBlock"
+          language="java"
+          since="0.1"
+          message="Avoid empty catch blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptycatchblock">
+        <description>
+            Empty Catch Block finds instances where an exception is caught, but nothing is done.
+            In most circumstances, this swallows an exception which should either be acted on
+            or reported.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement
+ [not(Block/BlockStatement)]
+ [$allowCommentedBlocks != true() or Block/@containsComment = false()]
+ [FormalParameter/Type/ReferenceType
+   /ClassOrInterfaceType[@Image != 'InterruptedException' and @Image != 'CloneNotSupportedException']
+ ]
+ [FormalParameter/VariableDeclaratorId[not(matches(@Name, $allowExceptionNameRegex))]]
+]]>
+                </value>
+            </property>
+            <property name="allowCommentedBlocks" type="Boolean" description="Empty blocks containing comments will be skipped" value="false"/>
+            <property name="allowExceptionNameRegex" type="String" description="Empty blocks catching exceptions with names matching this regular expression will be skipped" value="^(ignored|expected)$"/>
+        </properties>
+        <example>
+            <![CDATA[
+public void doSomething() {
+    try {
+        FileInputStream fis = new FileInputStream("/tmp/bugger");
+    } catch (IOException ioe) {
+        // not good
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinalizer"
+          language="java"
+          since="1.5"
+          message="Avoid empty finalize methods"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinalizer">
+        <description>
+            Empty finalize methods serve no purpose and should be removed. Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Name='finalize'][@Arity = 0]
+  /Block[not(*)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+   protected void finalize() {}
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinallyBlock"
+          language="java"
+          since="0.4"
+          message="Avoid empty finally blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinallyblock">
+        <description>
+            Empty finally blocks serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//FinallyStatement[not(Block/BlockStatement)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            int x=2;
+        } finally {
+            // empty!
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyIfStmt"
+          language="java"
+          since="0.1"
+          message="Avoid empty 'if' statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyifstmt">
+        <description>
+            Empty If Statement finds instances where a condition is checked but nothing is done about it.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//IfStatement/Statement
+ [EmptyStatement or Block[not(*)]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+ void bar(int x) {
+  if (x == 0) {
+   // empty!
+  }
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyInitializer"
+          language="java"
+          since="5.0"
+          message="Empty initializer was found"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyinitializer">
+        <description>
+            Empty initializers serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Initializer/Block[not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   static {} // Why ?
+
+   {} // Again, why ?
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyStatementBlock"
+          language="java"
+          since="5.0"
+          message="Avoid empty block statements."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptystatementblock">
+        <description>
+            Empty block statements serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//BlockStatement/Statement/Block[not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private int _bar;
+
+   public void setBar(int bar) {
+      { _bar = bar; } // Why not?
+      {} // But remove this.
+   }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyStatementNotInLoop"
+          language="java"
+          since="1.5"
+          message="An empty statement (semicolon) not part of a loop"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptystatementnotinloop">
+        <description>
+            An empty statement (or a semicolon by itself) that is not used as the sole body of a 'for'
+            or 'while' loop is probably a bug.  It could also be a double semicolon, which has no purpose
+            and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EmptyStatement
+ [not(
+       ../../../ForStatement
+       or ../../../WhileStatement
+       or ../../../BlockStatement/ClassOrInterfaceDeclaration
+       or ../../../../../../ForStatement/Statement[1]
+        /Block[1]/BlockStatement[1]/Statement/EmptyStatement
+       or ../../../../../../WhileStatement/Statement[1]
+        /Block[1]/BlockStatement[1]/Statement/EmptyStatement)
+ ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void doit() {
+      // this is probably not what you meant to do
+      ;
+      // the extra semicolon here this is not necessary
+      System.out.println("look at the extra semicolon");;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptySwitchStatements"

Review comment:
       This rule is enabled in our repo

##########
File path: check-rules/errorprone.xml
##########
@@ -0,0 +1,3721 @@
+<?xml version="1.0"?>
+
+<ruleset name="Error Prone"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+    <description>
+        Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
+    </description>
+
+    <rule name="AssignmentInOperand"
+          language="java"
+          since="1.03"
+          message="Avoid assignments in operands"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentInOperandRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmentinoperand">
+        <description>
+            Avoid assignments in operands; this can make code more complicated and harder to read.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    if ((x = getX()) == 3) {
+      System.out.println("3!");
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AssignmentToNonFinalStatic"
+          language="java"
+          since="2.2"
+          message="Possible unsafe assignment to a non-final static field in a constructor."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentToNonFinalStaticRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmenttononfinalstatic">
+        <description>
+            Identifies a possible unsafe usage of a static field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class StaticField {
+   static int x;
+   public FinalFields(int y) {
+    x = y; // unsafe
+   }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAccessibilityAlteration"
+          language="java"
+          since="4.1"
+          message="You should not modify visibility of class or methods using getDeclaredConstructors(), getDeclaredConstructor(Class[]), setAccessible() or PrivilegedAction."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidaccessibilityalteration">
+        <description>
+            Methods such as getDeclaredConstructors(), getDeclaredConstructor(Class[]) and setAccessible(),
+            as the interface PrivilegedAction, allow for the runtime alteration of variable, class, or
+            method visibility, even if they are private. This violates the principle of encapsulation.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimaryExpression[
+(
+(PrimarySuffix[
+        ends-with(@Image,'getDeclaredConstructors')
+                or
+        ends-with(@Image,'getDeclaredConstructor')
+                or
+        ends-with(@Image,'setAccessible')
+        ])
+or
+(PrimaryPrefix/Name[
+        ends-with(@Image,'getDeclaredConstructor')
+        or
+        ends-with(@Image,'getDeclaredConstructors')
+        or
+        starts-with(@Image,'AccessibleObject.setAccessible')
+        ])
+)
+and
+(//ImportDeclaration/Name[
+        contains(@Image,'java.security.PrivilegedAction')])
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+
+public class Violation {
+  public void invalidCallsInMethod() throws SecurityException, NoSuchMethodException {
+    // Possible call to forbidden getDeclaredConstructors
+    Class[] arrayOfClass = new Class[1];
+    this.getClass().getDeclaredConstructors();
+    this.getClass().getDeclaredConstructor(arrayOfClass);
+    Class clazz = this.getClass();
+    clazz.getDeclaredConstructor(arrayOfClass);
+    clazz.getDeclaredConstructors();
+      // Possible call to forbidden setAccessible
+    clazz.getMethod("", arrayOfClass).setAccessible(false);
+    AccessibleObject.setAccessible(null, false);
+    Method.setAccessible(null, false);
+    Method[] methodsArray = clazz.getMethods();
+    int nbMethod;
+    for ( nbMethod = 0; nbMethod < methodsArray.length; nbMethod++ ) {
+      methodsArray[nbMethod].setAccessible(false);
+    }
+
+      // Possible call to forbidden PrivilegedAction
+    PrivilegedAction priv = (PrivilegedAction) new Object(); priv.run();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAssertAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using assert as an identifier; it became a reserved word in JDK 1.4"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidassertasidentifier">
+        <description>
+            Use of the term 'assert' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='assert']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String assert = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidBranchingStatementAsLastInLoop"
+          language="java"
+          since="5.0"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidBranchingStatementAsLastInLoopRule"
+          message="Avoid using a branching statement as the last in a loop."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidbranchingstatementaslastinloop">
+        <description>
+            Using a branching statement as the last part of a loop may be a bug, and/or is confusing.
+            Ensure that the usage is not a bug, or consider using another approach.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// unusual use of branching statement in a loop
+for (int i = 0; i < 10; i++) {
+    if (i*i <= 25) {
+        continue;
+    }
+    break;
+}
+
+// this makes more sense...
+for (int i = 0; i < 10; i++) {
+    if (i*i > 25) {
+        break;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCallingFinalize"
+          language="java"
+          since="3.0"
+          message="Avoid calling finalize() explicitly"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCallingFinalizeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcallingfinalize">
+        <description>
+            The method Object.finalize() is called by the garbage collector on an object when garbage collection determines
+            that there are no more references to the object. It should not be invoked by application logic.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+void foo() {
+    Bar b = new Bar();
+    b.finalize();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingNPE"
+          language="java"
+          since="1.8"
+          message="Avoid catching NullPointerException; consider removing the cause of the NPE."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingnpe">
+        <description>
+            Code should never throw NullPointerExceptions under normal circumstances.  A catch block may hide the
+            original error, causing other, more subtle problems later on.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter/Type
+ /ReferenceType/ClassOrInterfaceType[@Image='NullPointerException']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    void bar() {
+        try {
+            // do something
+        } catch (NullPointerException npe) {
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingThrowable"
+          language="java"
+          since="1.2"
+          message="A catch statement should never catch throwable since it includes errors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCatchingThrowableRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingthrowable">
+        <description>
+            Catching Throwable errors is not recommended since its scope is very broad. It includes runtime issues such as
+            OutOfMemoryError that should be exposed and managed separately.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (Throwable th) {  // should not catch Throwable
+        th.printStackTrace();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDecimalLiteralsInBigDecimalConstructor"
+          language="java"
+          since="3.4"
+          message="Avoid creating BigDecimal with a decimal (float/double) literal. Use a String literal"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoiddecimalliteralsinbigdecimalconstructor">
+        <description>
+            One might assume that the result of "new BigDecimal(0.1)" is exactly equal to 0.1, but it is actually
+            equal to .1000000000000000055511151231257827021181583404541015625.
+            This is because 0.1 cannot be represented exactly as a double (or as a binary fraction of any finite
+            length). Thus, the long value that is being passed in to the constructor is not exactly equal to 0.1,
+            appearances notwithstanding.
+
+            The (String) constructor, on the other hand, is perfectly predictable: 'new BigDecimal("0.1")' is
+            exactly equal to 0.1, as one would expect.  Therefore, it is generally recommended that the
+            (String) constructor be used in preference to this one.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//AllocationExpression[pmd-java:typeIs('java.math.BigDecimal')]
+[Arguments/ArgumentList/Expression/PrimaryExpression
+    [
+        pmd-java:typeIs('float') or
+        pmd-java:typeIs('java.lang.Float') or
+        pmd-java:typeIs('double') or
+        pmd-java:typeIs('java.lang.Double')
+    ]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+BigDecimal bd = new BigDecimal(1.123);       // loss of precision, this would trigger the rule
+
+BigDecimal bd = new BigDecimal("1.123");     // preferred approach
+
+BigDecimal bd = new BigDecimal(12);          // preferred approach, ok for integer values
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDuplicateLiterals"
+          language="java"
+          since="1.0"
+          message="The String literal {0} appears {1} times in this file; the first occurrence is on line {2}"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidDuplicateLiteralsRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidduplicateliterals">
+        <description>
+            Code containing duplicate String literals can usually be improved by declaring the String as a constant field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private void bar() {
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+}
+private void buz(String x) {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidEnumAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using enum as an identifier; it's a reserved word in JDK 1.5"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidenumasidentifier">
+        <description>
+            Use of the term 'enum' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='enum']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String enum = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingMethodName"
+          language="java"
+          since="3.0"
+          message="Field {0} has the same name as a method"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingMethodNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingmethodname">
+        <description>
+            It can be confusing to have a field name with the same name as a method. While this is permitted,
+            having information (field) and actions (method) is not clear naming. Developers versed in
+            Smalltalk often prefer this approach as the methods denote accessor methods.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+    Object bar;
+    // bar is data or an action or both?
+    void bar() {
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingTypeName"
+          language="java"
+          since="3.0"
+          message="It is somewhat confusing to have a field name matching the declaring class name"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingTypeNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingtypename">
+        <description>
+            It is somewhat confusing to have a field name matching the declaring type name.
+            This probably means that type and/or field names should be chosen more carefully.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo extends Bar {
+    int foo;    // There is probably a better name that can be used
+}
+public interface Operation {
+    int OPERATION = 1; // There is probably a better name that can be used
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidInstanceofChecksInCatchClause"
+          language="java"
+          since="3.0"
+          message="An instanceof check is being performed on the caught exception.  Create a separate catch clause for this exception type."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidinstanceofchecksincatchclause">
+        <description>
+            Each caught exception type should be handled in its own catch clause.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter
+ /following-sibling::Block//InstanceOfExpression/PrimaryExpression/PrimaryPrefix
+  /Name[
+   @Image = ./ancestor::Block/preceding-sibling::FormalParameter
+    /VariableDeclaratorId/@Name
+  ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+try { // Avoid this
+    // do something
+} catch (Exception ee) {
+    if (ee instanceof IOException) {
+        cleanup();
+    }
+}
+
+try {  // Prefer this:
+    // do something
+} catch (IOException ee) {
+    cleanup();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLiteralsInIfCondition"
+          language="java"
+          since="4.2.6"
+          message="Avoid using Literals in Conditional Statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidliteralsinifcondition">
+        <description>
+            Avoid using hard-coded literals in conditional statements. By declaring them as static variables
+            or private members with descriptive names maintainability is enhanced. By default, the literals "-1" and "0" are ignored.
+            More exceptions can be defined with the property "ignoreMagicNumbers".
+
+            The rule doesn't consider deeper expressions by default, but this can be enabled via the property `ignoreExpressions`.
+            With this property set to false, if-conditions like `i == 1 + 5` are reported as well. Note that in that case,
+            the property ignoreMagicNumbers is not taken into account, if there are multiple literals involved in such an expression.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="ignoreMagicNumbers"
+                      description="Comma-separated list of magic numbers, that should be ignored"
+                      type="String" value="-1,0"/>
+            <property name="ignoreExpressions"
+                      description="If true, only literals in simple if conditions are considered. Otherwise literals in expressions are checked, too."
+                      type="Boolean" value="true"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(: simple case - no deep expressions :)
+//IfStatement[$ignoreExpressions = true()]/Expression/*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider also deeper expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression//*[local-name() != 'UnaryExpression' or @Operator != '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider negative literals :)
+//IfStatement[$ignoreExpressions = false()]/Expression//UnaryExpression[@Operator = '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), concat('-', @Image)))]
+|
+(: consider multiple literals in expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression[count(*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]) > 1]
+]]>
+                </value>
+            </property>
+            <property name="version" value="2.0"/>
+        </properties>
+        <example>
+            <![CDATA[
+private static final int MAX_NUMBER_OF_REQUESTS = 10;
+
+public void checkRequests() {
+
+    if (i == 10) {                        // magic number, buried in a method
+      doSomething();
+    }
+
+    if (i == MAX_NUMBER_OF_REQUESTS) {    // preferred approach
+      doSomething();
+    }
+
+    if (aString.indexOf('.') != -1) {}     // magic number -1, by default ignored
+    if (aString.indexOf('.') >= 0) { }     // alternative approach
+
+    if (aDouble > 0.0) {}                  // magic number 0.0
+    if (aDouble >= Double.MIN_VALUE) {}    // preferred approach
+
+    // with rule property "ignoreExpressions" set to "false"
+    if (i == pos + 5) {}  // violation: magic number 5 within an (additive) expression
+    if (i == pos + SUFFIX_LENGTH) {} // preferred approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLosingExceptionInformation"
+          since="4.2.6"
+          language="java"
+          message="Avoid statements in a catch block that invoke accessors on the exception without using the information"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidlosingexceptioninformation">
+        <description>
+            Statements in a catch block that invoke accessors on the exception without using the information
+            only add to code size.  Either remove the invocation, or use the return result.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/Block/BlockStatement/Statement/StatementExpression/PrimaryExpression/PrimaryPrefix/Name
+[
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getLocalizedMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getCause')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getStackTrace')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.toString')
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (SomeException se) {
+        se.getMessage();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidMultipleUnaryOperators"
+          language="java"
+          since="4.2"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidMultipleUnaryOperatorsRule"
+          message="Using multiple unary operators may be a bug, and/or is confusing."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidmultipleunaryoperators">
+        <description>
+            The use of multiple unary operators may be problematic, and/or confusing.
+            Ensure that the intended usage is not a bug, or consider simplifying the expression.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// These are typo bugs, or at best needlessly complex and confusing:
+int i = - -1;
+int j = + - +1;
+int z = ~~2;
+boolean b = !!true;
+boolean c = !!!true;
+
+// These are better:
+int i = 1;
+int j = -1;
+int z = 2;
+boolean b = true;
+boolean c = false;
+
+// And these just make your brain hurt:
+int i = ~-2;
+int j = -~7;
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidUsingOctalValues"
+          language="java"
+          since="3.9"
+          message="Do not start a literal by 0 unless it's an octal value"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidUsingOctalValuesRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidusingoctalvalues">
+        <description>
+            Integer literals should not start with zero since this denotes that the rest of literal will be
+            interpreted as an octal value.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+int i = 012;    // set i with 10 not 12
+int j = 010;    // set j with 8 not 10
+k = i * j;      // set k with 80 not 120
+]]>
+        </example>
+    </rule>
+
+    <rule name="BadComparison" ref="ComparisonWithNaN" deprecated="true" />
+
+    <rule name="BeanMembersShouldSerialize"
+          language="java"
+          since="1.1"
+          message="Found non-transient, non-static member. Please mark as transient or provide accessors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BeanMembersShouldSerializeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#beanmembersshouldserialize">
+        <description>
+            If a class is a bean, or is referenced by a bean directly or indirectly it needs to be serializable.
+            Member variables need to be marked as transient, static, or have accessor methods in the class. Marking
+            variables as transient is the safest and easiest modification. Accessor methods should follow the Java
+            naming conventions, i.e. for a variable named foo, getFoo() and setFoo() accessor methods should be provided.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private transient int someFoo;  // good, it's transient
+private static int otherFoo;    // also OK
+private int moreFoo;            // OK, has proper accessors, see below
+private int badFoo;             // bad, should be marked transient
+
+private void setMoreFoo(int moreFoo){
+      this.moreFoo = moreFoo;
+}
+
+private int getMoreFoo(){
+      return this.moreFoo;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="BrokenNullCheck"
+          language="java"
+          since="3.8"
+          message="Method call on object which may be null"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BrokenNullCheckRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#brokennullcheck">
+        <description>
+            The null check is broken since it will throw a NullPointerException itself.
+            It is likely that you used || instead of &amp;&amp; or vice versa.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+public String bar(String string) {
+  // should be &&
+    if (string!=null || !string.equals(""))
+        return string;
+  // should be ||
+    if (string==null && string.equals(""))
+        return string;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperFirst"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the start of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperfirst">
+        <description>Super should be called at the start of the method</description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='onCreate' or
+  @Name='onConfigurationChanged' or
+  @Name='onPostCreate' or
+  @Name='onPostResume' or
+  @Name='onRestart' or
+  @Name='onRestoreInstanceState' or
+  @Name='onResume' or
+  @Name='onStart'
+  ]
+    /Block[not(
+      (BlockStatement[1]/Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name]))]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onCreate(Bundle bundle) {
+        // missing call to super.onCreate(bundle)
+        foo();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperLast"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the end of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperlast">
+        <description>
+            Super should be called at the end of the method
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='finish' or
+  @Name='onDestroy' or
+  @Name='onPause' or
+  @Name='onSaveInstanceState' or
+  @Name='onStop' or
+  @Name='onTerminate'
+  ]
+   /Block/BlockStatement[last()]
+    [not(Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name])]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onPause() {
+        foo();
+        // missing call to super.onPause()
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CheckSkipResult"
+          language="java"
+          since="5.0"
+          message="Check the value returned by the skip() method of an InputStream to see if the requested number of bytes has been skipped."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CheckSkipResultRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#checkskipresult">
+        <description>
+            The skip() method may skip a smaller number of bytes than requested. Check the returned value to find out if it was the case or not.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private FileInputStream _s = new FileInputStream("file");
+
+   public void skip(int n) throws IOException {
+      _s.skip(n); // You are not sure that exactly n bytes are skipped
+   }
+
+   public void skipExactly(int n) throws IOException {
+      while (n != 0) {
+         long skipped = _s.skip(n);
+         if (skipped == 0)
+            throw new EOFException();
+         n -= skipped;
+      }
+   }
+]]>
+        </example>
+    </rule>
+
+    <rule name="ClassCastExceptionWithToArray"
+          language="java"
+          since="3.4"
+          message="This usage of the Collection.toArray() method will throw a ClassCastException."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#classcastexceptionwithtoarray">
+        <description>
+            When deriving an array of a specific class from your Collection, one should provide an array of
+            the same class as the parameter of the toArray() method. Doing otherwise you will will result
+            in a ClassCastException.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CastExpression[Type/ReferenceType/ClassOrInterfaceType[@Image != "Object"]]
+    /PrimaryExpression
+    [PrimaryPrefix/Name[ends-with(@Image, '.toArray')]]
+    [PrimarySuffix/Arguments[not(*)]]
+    [count(PrimarySuffix) = 1]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+Collection c = new ArrayList();
+Integer obj = new Integer(1);
+c.add(obj);
+
+    // this would trigger the rule (and throw a ClassCastException if executed)
+Integer[] a = (Integer [])c.toArray();
+
+   // this is fine and will not trigger the rule
+Integer[] b = (Integer [])c.toArray(new Integer[c.size()]);
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustBePublic"
+          language="java"
+          since="5.4.0"
+          message="clone() method must be public if the class implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustbepublic">
+        <description>
+            The java Manual says "By convention, classes that implement this interface should override
+            Object.clone (which is protected) with a public method."
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Public= false()]
+  [@Name = 'clone']
+  [@Arity = 0]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() throws CloneNotSupportedException { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    protected Foo clone() { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Object clone() // Ok
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustImplementCloneable"
+          language="java"
+          since="1.9"
+          message="clone() method should be implemented only if implementing Cloneable interface"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloneMethodMustImplementCloneableRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustimplementcloneable">
+        <description>
+            The method clone() should only be implemented if the class implements the Cloneable interface with the exception of
+            a final method that only throws CloneNotSupportedException.
+
+            The rule can also detect, if the class implements or extends a Cloneable class.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class MyClass {
+ public Object clone() throws CloneNotSupportedException {
+  return foo;
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodReturnTypeMustMatchClassName"
+          language="java"
+          minimumLanguageVersion="1.5"
+          since="5.4.0"
+          message="The return type of the clone() method must be the class name when implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodreturntypemustmatchclassname">
+        <description>
+            If a class implements cloneable the return type of the method clone() must be the class name. That way, the caller
+            of the clone method doesn't need to cast the returned clone to the correct type.
+
+            Note: This is only possible with Java 1.5 or higher.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and not (ResultType//ClassOrInterfaceType/@Image = ancestor::ClassOrInterfaceDeclaration[1]/@SimpleName)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() { // Violation, Object must be Foo
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Foo clone() { //Ok
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneThrowsCloneNotSupportedException"
+          deprecated="true"
+          language="java"
+          since="1.9"
+          message="clone() method should throw CloneNotSupportedException"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonethrowsclonenotsupportedexception">
+        <description>
+            The method clone() should throw a CloneNotSupportedException.
+
+            This rule is deprecated since PMD 6.35.0 without replacement. The rule has no real value as
+            `CloneNotSupportedException` is a checked exception and therefore you need to deal with it while
+            implementing the `clone()` method. You either need to declare the exception or catch it. If you catch it,
+            then subclasses can't throw it themselves explicitly. However, `Object.clone()` will still throw this
+            exception if the `Cloneable` interface is not implemented.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and count(NameList/Name[contains
+(@Image,'CloneNotSupportedException')]) = 0
+]
+[
+../../../../ClassOrInterfaceDeclaration[@Final = false()]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyClass implements Cloneable{
+    public Object clone() { // will cause an error
+         MyClass clone = (MyClass)super.clone();
+         return clone;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloseResource"
+          language="java"
+          since="1.2.2"
+          message="Ensure that resources like this {0} object are closed after use"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloseResourceRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#closeresource">
+        <description>
+            Ensure that resources (like `java.sql.Connection`, `java.sql.Statement`, and `java.sql.ResultSet` objects
+            and any subtype of `java.lang.AutoCloseable`) are always closed after use.
+            Failing to do so might result in resource leaks.
+
+            Note: It suffices to configure the super type, e.g. `java.lang.AutoClosable`, so that this rule automatically triggers
+            on any subtype (e.g. `java.io.FileInputStream`). Additionally specifying `java.sql.Connection` helps in detecting
+            the types, if the type resolution / auxclasspath is not correctly setup.
+
+            Note: Since PMD 6.16.0 the default value for the property `types` contains `java.lang.AutoCloseable` and detects
+            now cases where the standard `java.io.*Stream` classes are involved. In order to restore the old behaviour,
+            just remove "AutoCloseable" from the types.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Bar {
+    public void withSQL() {
+        Connection c = pool.getConnection();
+        try {
+            // do stuff
+        } catch (SQLException ex) {
+           // handle exception
+        } finally {
+            // oops, should close the connection using 'close'!
+            // c.close();
+        }
+    }
+
+    public void withFile() {
+        InputStream file = new FileInputStream(new File("/tmp/foo"));
+        try {
+            int c = file.in();
+        } catch (IOException e) {
+            // handle exception
+        } finally {
+            // TODO: close file
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CompareObjectsWithEquals"
+          language="java"
+          since="3.2"
+          message="Use equals() to compare object references."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#compareobjectswithequals">
+        <description>
+            Use `equals()` to compare object references; avoid comparing them with `==`.
+
+            Since comparing objects with named constants is useful in some cases (eg, when
+            defining constants for sentinel values), the rule ignores comparisons against
+            fields with all-caps name (eg `this == SENTINEL`), which is a common naming
+            convention for constant fields.
+
+            You may allow some types to be compared by reference by listing the exceptions
+            in the `typesThatCompareByReference` property.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="typesThatCompareByReference" type="List[String]" delimiter="," description="List of canonical type names for which reference comparison is allowed.">
+                <value>java.lang.Enum,java.lang.Class</value>
+            </property>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EqualityExpression
+    [count(
+        PrimaryExpression[pmd-java:typeIs('java.lang.Object')]
+        [not(some $t in $typesThatCompareByReference satisfies pmd-java:typeIs($t))]
+       ) = 2
+    ]
+    [not(PrimaryExpression[PrimaryPrefix/@ThisModifier = true()]
+                          [not(PrimarySuffix)]
+                          [ancestor::MethodDeclaration[@Name = 'equals']])
+    ]
+    (: Is not a field access with an all-caps identifier :)
+    [not(PrimaryExpression[not(PrimarySuffix) and PrimaryPrefix/Name[upper-case(@Image)=@Image]
+     or PrimaryExpression/PrimarySuffix[last()][upper-case(@Image)=@Image]])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+class Foo {
+  boolean bar(String a, String b) {
+    return a == b;
+  }
+}
+
+]]>
+        </example>
+    </rule>
+
+    <rule name="ComparisonWithNaN"
+          language="java"
+          since="6.36.0"
+          message="Comparisons with NaN always return false"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+        <description><![CDATA[
+            Reports comparisons with double and float `NaN` (Not-a-Number) values.
+            These are [specified](https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.21.1)
+            to have unintuitive behavior: NaN is considered unequal to itself.
+            This means a check like `someDouble == Double.NaN` will always return
+            false, even if `someDouble` is really the NaN value. To test whether a
+            value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+            (or `Float.isNaN`). The `!=` operator should be treated similarly.
+            Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+            and will always evaluate to false.
+
+            This rule has been renamed from "BadComparison" with PMD 6.36.0.
+        ]]></description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+        </example>
+    </rule>
+
+
+    <rule name="ConstructorCallsOverridableMethod"
+          language="java"
+          since="1.04"
+          message="Overridable {0} called during object construction"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#constructorcallsoverridablemethod">
+        <description>
+            Calling overridable methods during construction poses a risk of invoking methods on an incompletely
+            constructed object and can be difficult to debug.
+            It may leave the sub-class unable to construct its superclass or forced to replicate the construction
+            process completely within itself, losing the ability to call super().  If the default constructor
+            contains a call to an overridable method, the subclass may be completely uninstantiable.   Note that
+            this includes method calls throughout the control flow graph - i.e., if a constructor Foo() calls a
+            private method bar() that calls a public method buz(), this denotes a problem.
+        </description>
+        <priority>1</priority>
+        <example>
+            <![CDATA[
+public class SeniorClass {
+  public SeniorClass(){
+      toString(); //may throw NullPointerException if overridden
+  }
+  public String toString(){
+    return "IAmSeniorClass";
+  }
+}
+public class JuniorClass extends SeniorClass {
+  private String name;
+  public JuniorClass(){
+    super(); //Automatic call leads to NullPointerException
+    name = "JuniorClass";
+  }
+  public String toString(){
+    return name.toUpperCase();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DataflowAnomalyAnalysis"
+          language="java"
+          since="3.9"
+          message="Found ''{0}''-anomaly for variable ''{1}'' (lines ''{2}''-''{3}'')."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DataflowAnomalyAnalysisRule"
+          dfa="true"
+          deprecated="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dataflowanomalyanalysis">
+        <description>The dataflow analysis tracks local definitions, undefinitions and references to variables on different paths on the data flow.
+            From those informations there can be found various problems.
+
+            1. DU - Anomaly: A recently defined variable is undefined. These anomalies may appear in normal source text.
+            2. DD - Anomaly: A recently defined variable is redefined. This is ominous but don't have to be a bug.
+
+            This rule is deprecated. Use {% rule "java/bestpractices/UnusedAssignment" %} in category bestpractices instead.
+        </description>
+        <priority>5</priority>
+        <example>
+            <![CDATA[
+public void foo() {
+  int buz = 5;
+  buz = 6; // redefinition of buz -> dd-anomaly
+  foo(buz);
+  buz = 2;
+} // buz is undefined when leaving scope -> du-anomaly
+]]>
+        </example>
+    </rule>
+
+    <rule name="DetachedTestCase"
+          language="java"
+          since="6.13.0"
+          message="Probable detached JUnit test case."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#detachedtestcase">
+        <description>
+            The method appears to be a test case since it has public or default visibility,
+            non-static access, no arguments, no return value, has no annotations, but is a
+            member of a class that has one or more JUnit test cases. If it is a utility
+            method, it should likely have private visibility. If it is an ignored test, it
+            should be annotated with @Test and @Ignore.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value><![CDATA[
+//ClassOrInterfaceBodyDeclaration
+[../ClassOrInterfaceBodyDeclaration/Annotation/*/Name
+        [pmd-java:typeIs('org.junit.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestFactory')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
+         or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')]
+]
+[not(Annotation)]
+[MethodDeclaration[(@Public = true() or @PackagePrivate = true()) and @Static = false() and
+        ResultType[@Void = true()] and
+        MethodDeclarator/FormalParameters[@Size = 0]
+    ]
+]
+]]></value>
+            </property>
+            <property name="version" value="2.0" />
+        </properties>
+        <example>
+            <![CDATA[
+public class MyTest {
+    @Test
+    public void someTest() {
+    }
+
+    // violation: Not annotated
+    public void someOtherTest () {
+    }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallGarbageCollectionExplicitly"
+          language="java"
+          since="4.2"
+          message="Do not explicitly trigger a garbage collection."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotcallgarbagecollectionexplicitly">
+        <description>
+            Calls to System.gc(), Runtime.getRuntime().gc(), and System.runFinalization() are not advised. Code should have the
+            same behavior whether the garbage collection is disabled using the option -Xdisableexplicitgc or not.
+            Moreover, "modern" jvms do a very good job handling garbage collections. If memory usage issues unrelated to memory
+            leaks develop within an application, it should be dealt with JVM options rather than within the code itself.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+(starts-with(@Image, 'System.') and
+(starts-with(@Image, 'System.gc') or
+starts-with(@Image, 'System.runFinalization'))) or
+(
+starts-with(@Image,'Runtime.getRuntime') and
+../../PrimarySuffix[ends-with(@Image,'gc')]
+)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class GCCall {
+    public GCCall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+
+    public explicitGCcall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallSystemExit" ref="category/java/errorprone.xml/DoNotTerminateVM" deprecated="true" />
+
+    <rule name="DoNotExtendJavaLangThrowable"
+          language="java"
+          since="6.0.0"
+          message="Exceptions should not extend java.lang.Throwable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotextendjavalangthrowable">
+        <description>
+            Extend Exception or RuntimeException instead of Throwable.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration/ExtendsList/ClassOrInterfaceType
+  [@Image="Throwable" or @Image="java.lang.Throwable"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo extends Throwable { }
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotHardCodeSDCard"
+          since="4.2.6"
+          language="java"
+          message="Do not hardcode /sdcard."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donothardcodesdcard">
+        <description>
+            Use Environment.getExternalStorageDirectory() instead of "/sdcard"
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Literal[starts-with(@Image,'"/sdcard')]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyActivity extends Activity {
+    protected void foo() {
+        String storageLocation = "/sdcard/mypackage";   // hard-coded, poor approach
+
+       storageLocation = Environment.getExternalStorageDirectory() + "/mypackage"; // preferred approach
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotTerminateVM"
+          language="java"
+          since="4.1"
+          message="System.exit() should not be used in J2EE/JEE apps"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotterminatevm">
+        <description>
+            Web applications should not call `System.exit()`, since only the web container or the
+            application server should stop the JVM. Otherwise a web application would terminate all other applications
+            running on the same application server.
+
+            This rule also checks for the equivalent calls `Runtime.getRuntime().exit()` and `Runtime.getRuntime().halt()`.
+
+            This rule was called *DoNotCallSystemExit* until PMD 6.29.0.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+    starts-with(@Image,'System.exit')
+    or
+    (starts-with(@Image,'Runtime.getRuntime') and ../../PrimarySuffix[ends-with(@Image,'exit') or ends-with(@Image,'halt')])
+][not(ancestor::MethodDeclaration[1][@Name="main" and @Static = true()])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    System.exit(0);                 // never call this when running in an application server!
+}
+public void foo() {
+    Runtime.getRuntime().exit(0);   // never stop the JVM manually, the container will do this.
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotThrowExceptionInFinally"
+          language="java"
+          since="4.2"
+          message="A throw statement in a finally block makes the control flow hard to understand."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotthrowexceptioninfinally">
+        <description>
+            Throwing exceptions within a 'finally' block is confusing since they may mask other exceptions
+            or code defects.
+            Note: This is a PMD implementation of the Lint4j rule "A throw in a finally block"
+        </description>
+        <priority>4</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//FinallyStatement[descendant::ThrowStatement]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            // Here do some stuff
+        } catch( Exception e) {
+            // Handling the issue
+        } finally {
+            // is this really a good idea ?
+            throw new Exception();
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontImportSun"
+          language="java"
+          since="1.5"
+          message="Avoid importing anything from the 'sun.*' packages"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DontImportSunRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontimportsun">
+        <description>
+            Avoid importing anything from the 'sun.*' packages.  These packages are not portable and are likely to change.
+        </description>
+        <priority>4</priority>
+        <example>
+            <![CDATA[
+import sun.misc.foo;
+public class Foo {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontUseFloatTypeForLoopIndices"
+          language="java"
+          since="4.3"
+          message="Don't use floating point for loop indices. If you must use floating point, use double."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontusefloattypeforloopindices">
+        <description>
+            Don't use floating point for loop indices. If you must use floating point, use double
+            unless you're certain that float provides enough precision and you have a compelling
+            performance need (space or time).
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ForStatement/ForInit/LocalVariableDeclaration
+/Type/PrimitiveType[@Image="float"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Count {
+  public static void main(String[] args) {
+    final int START = 2000000000;
+    int count = 0;
+    for (float f = START; f < START + 50; f++)
+      count++;
+      //Prints 0 because (float) START == (float) (START + 50).
+      System.out.println(count);
+      //The termination test misbehaves due to floating point granularity.
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyCatchBlock"
+          language="java"
+          since="0.1"
+          message="Avoid empty catch blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptycatchblock">
+        <description>
+            Empty Catch Block finds instances where an exception is caught, but nothing is done.
+            In most circumstances, this swallows an exception which should either be acted on
+            or reported.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement
+ [not(Block/BlockStatement)]
+ [$allowCommentedBlocks != true() or Block/@containsComment = false()]
+ [FormalParameter/Type/ReferenceType
+   /ClassOrInterfaceType[@Image != 'InterruptedException' and @Image != 'CloneNotSupportedException']
+ ]
+ [FormalParameter/VariableDeclaratorId[not(matches(@Name, $allowExceptionNameRegex))]]
+]]>
+                </value>
+            </property>
+            <property name="allowCommentedBlocks" type="Boolean" description="Empty blocks containing comments will be skipped" value="false"/>
+            <property name="allowExceptionNameRegex" type="String" description="Empty blocks catching exceptions with names matching this regular expression will be skipped" value="^(ignored|expected)$"/>
+        </properties>
+        <example>
+            <![CDATA[
+public void doSomething() {
+    try {
+        FileInputStream fis = new FileInputStream("/tmp/bugger");
+    } catch (IOException ioe) {
+        // not good
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinalizer"
+          language="java"
+          since="1.5"
+          message="Avoid empty finalize methods"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinalizer">
+        <description>
+            Empty finalize methods serve no purpose and should be removed. Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Name='finalize'][@Arity = 0]
+  /Block[not(*)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+   protected void finalize() {}
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinallyBlock"
+          language="java"
+          since="0.4"
+          message="Avoid empty finally blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinallyblock">
+        <description>
+            Empty finally blocks serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//FinallyStatement[not(Block/BlockStatement)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            int x=2;
+        } finally {
+            // empty!
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyIfStmt"
+          language="java"
+          since="0.1"
+          message="Avoid empty 'if' statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyifstmt">
+        <description>
+            Empty If Statement finds instances where a condition is checked but nothing is done about it.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//IfStatement/Statement
+ [EmptyStatement or Block[not(*)]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+ void bar(int x) {
+  if (x == 0) {
+   // empty!
+  }
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyInitializer"
+          language="java"
+          since="5.0"
+          message="Empty initializer was found"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyinitializer">
+        <description>
+            Empty initializers serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Initializer/Block[not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   static {} // Why ?
+
+   {} // Again, why ?
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyStatementBlock"
+          language="java"
+          since="5.0"
+          message="Avoid empty block statements."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptystatementblock">
+        <description>
+            Empty block statements serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//BlockStatement/Statement/Block[not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private int _bar;
+
+   public void setBar(int bar) {
+      { _bar = bar; } // Why not?
+      {} // But remove this.
+   }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyStatementNotInLoop"

Review comment:
       This rule is enabled in our repo

##########
File path: check-rules/errorprone.xml
##########
@@ -0,0 +1,3721 @@
+<?xml version="1.0"?>
+
+<ruleset name="Error Prone"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+    <description>
+        Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
+    </description>
+
+    <rule name="AssignmentInOperand"
+          language="java"
+          since="1.03"
+          message="Avoid assignments in operands"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentInOperandRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmentinoperand">
+        <description>
+            Avoid assignments in operands; this can make code more complicated and harder to read.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    if ((x = getX()) == 3) {
+      System.out.println("3!");
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AssignmentToNonFinalStatic"
+          language="java"
+          since="2.2"
+          message="Possible unsafe assignment to a non-final static field in a constructor."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentToNonFinalStaticRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmenttononfinalstatic">
+        <description>
+            Identifies a possible unsafe usage of a static field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class StaticField {
+   static int x;
+   public FinalFields(int y) {
+    x = y; // unsafe
+   }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAccessibilityAlteration"
+          language="java"
+          since="4.1"
+          message="You should not modify visibility of class or methods using getDeclaredConstructors(), getDeclaredConstructor(Class[]), setAccessible() or PrivilegedAction."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidaccessibilityalteration">
+        <description>
+            Methods such as getDeclaredConstructors(), getDeclaredConstructor(Class[]) and setAccessible(),
+            as the interface PrivilegedAction, allow for the runtime alteration of variable, class, or
+            method visibility, even if they are private. This violates the principle of encapsulation.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimaryExpression[
+(
+(PrimarySuffix[
+        ends-with(@Image,'getDeclaredConstructors')
+                or
+        ends-with(@Image,'getDeclaredConstructor')
+                or
+        ends-with(@Image,'setAccessible')
+        ])
+or
+(PrimaryPrefix/Name[
+        ends-with(@Image,'getDeclaredConstructor')
+        or
+        ends-with(@Image,'getDeclaredConstructors')
+        or
+        starts-with(@Image,'AccessibleObject.setAccessible')
+        ])
+)
+and
+(//ImportDeclaration/Name[
+        contains(@Image,'java.security.PrivilegedAction')])
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+
+public class Violation {
+  public void invalidCallsInMethod() throws SecurityException, NoSuchMethodException {
+    // Possible call to forbidden getDeclaredConstructors
+    Class[] arrayOfClass = new Class[1];
+    this.getClass().getDeclaredConstructors();
+    this.getClass().getDeclaredConstructor(arrayOfClass);
+    Class clazz = this.getClass();
+    clazz.getDeclaredConstructor(arrayOfClass);
+    clazz.getDeclaredConstructors();
+      // Possible call to forbidden setAccessible
+    clazz.getMethod("", arrayOfClass).setAccessible(false);
+    AccessibleObject.setAccessible(null, false);
+    Method.setAccessible(null, false);
+    Method[] methodsArray = clazz.getMethods();
+    int nbMethod;
+    for ( nbMethod = 0; nbMethod < methodsArray.length; nbMethod++ ) {
+      methodsArray[nbMethod].setAccessible(false);
+    }
+
+      // Possible call to forbidden PrivilegedAction
+    PrivilegedAction priv = (PrivilegedAction) new Object(); priv.run();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAssertAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using assert as an identifier; it became a reserved word in JDK 1.4"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidassertasidentifier">
+        <description>
+            Use of the term 'assert' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='assert']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String assert = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidBranchingStatementAsLastInLoop"
+          language="java"
+          since="5.0"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidBranchingStatementAsLastInLoopRule"
+          message="Avoid using a branching statement as the last in a loop."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidbranchingstatementaslastinloop">
+        <description>
+            Using a branching statement as the last part of a loop may be a bug, and/or is confusing.
+            Ensure that the usage is not a bug, or consider using another approach.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// unusual use of branching statement in a loop
+for (int i = 0; i < 10; i++) {
+    if (i*i <= 25) {
+        continue;
+    }
+    break;
+}
+
+// this makes more sense...
+for (int i = 0; i < 10; i++) {
+    if (i*i > 25) {
+        break;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCallingFinalize"
+          language="java"
+          since="3.0"
+          message="Avoid calling finalize() explicitly"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCallingFinalizeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcallingfinalize">
+        <description>
+            The method Object.finalize() is called by the garbage collector on an object when garbage collection determines
+            that there are no more references to the object. It should not be invoked by application logic.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+void foo() {
+    Bar b = new Bar();
+    b.finalize();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingNPE"
+          language="java"
+          since="1.8"
+          message="Avoid catching NullPointerException; consider removing the cause of the NPE."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingnpe">
+        <description>
+            Code should never throw NullPointerExceptions under normal circumstances.  A catch block may hide the
+            original error, causing other, more subtle problems later on.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter/Type
+ /ReferenceType/ClassOrInterfaceType[@Image='NullPointerException']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    void bar() {
+        try {
+            // do something
+        } catch (NullPointerException npe) {
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingThrowable"
+          language="java"
+          since="1.2"
+          message="A catch statement should never catch throwable since it includes errors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCatchingThrowableRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingthrowable">
+        <description>
+            Catching Throwable errors is not recommended since its scope is very broad. It includes runtime issues such as
+            OutOfMemoryError that should be exposed and managed separately.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (Throwable th) {  // should not catch Throwable
+        th.printStackTrace();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDecimalLiteralsInBigDecimalConstructor"
+          language="java"
+          since="3.4"
+          message="Avoid creating BigDecimal with a decimal (float/double) literal. Use a String literal"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoiddecimalliteralsinbigdecimalconstructor">
+        <description>
+            One might assume that the result of "new BigDecimal(0.1)" is exactly equal to 0.1, but it is actually
+            equal to .1000000000000000055511151231257827021181583404541015625.
+            This is because 0.1 cannot be represented exactly as a double (or as a binary fraction of any finite
+            length). Thus, the long value that is being passed in to the constructor is not exactly equal to 0.1,
+            appearances notwithstanding.
+
+            The (String) constructor, on the other hand, is perfectly predictable: 'new BigDecimal("0.1")' is
+            exactly equal to 0.1, as one would expect.  Therefore, it is generally recommended that the
+            (String) constructor be used in preference to this one.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//AllocationExpression[pmd-java:typeIs('java.math.BigDecimal')]
+[Arguments/ArgumentList/Expression/PrimaryExpression
+    [
+        pmd-java:typeIs('float') or
+        pmd-java:typeIs('java.lang.Float') or
+        pmd-java:typeIs('double') or
+        pmd-java:typeIs('java.lang.Double')
+    ]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+BigDecimal bd = new BigDecimal(1.123);       // loss of precision, this would trigger the rule
+
+BigDecimal bd = new BigDecimal("1.123");     // preferred approach
+
+BigDecimal bd = new BigDecimal(12);          // preferred approach, ok for integer values
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDuplicateLiterals"
+          language="java"
+          since="1.0"
+          message="The String literal {0} appears {1} times in this file; the first occurrence is on line {2}"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidDuplicateLiteralsRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidduplicateliterals">
+        <description>
+            Code containing duplicate String literals can usually be improved by declaring the String as a constant field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private void bar() {
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+}
+private void buz(String x) {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidEnumAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using enum as an identifier; it's a reserved word in JDK 1.5"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidenumasidentifier">
+        <description>
+            Use of the term 'enum' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='enum']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String enum = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingMethodName"
+          language="java"
+          since="3.0"
+          message="Field {0} has the same name as a method"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingMethodNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingmethodname">
+        <description>
+            It can be confusing to have a field name with the same name as a method. While this is permitted,
+            having information (field) and actions (method) is not clear naming. Developers versed in
+            Smalltalk often prefer this approach as the methods denote accessor methods.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+    Object bar;
+    // bar is data or an action or both?
+    void bar() {
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingTypeName"
+          language="java"
+          since="3.0"
+          message="It is somewhat confusing to have a field name matching the declaring class name"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingTypeNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingtypename">
+        <description>
+            It is somewhat confusing to have a field name matching the declaring type name.
+            This probably means that type and/or field names should be chosen more carefully.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo extends Bar {
+    int foo;    // There is probably a better name that can be used
+}
+public interface Operation {
+    int OPERATION = 1; // There is probably a better name that can be used
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidInstanceofChecksInCatchClause"
+          language="java"
+          since="3.0"
+          message="An instanceof check is being performed on the caught exception.  Create a separate catch clause for this exception type."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidinstanceofchecksincatchclause">
+        <description>
+            Each caught exception type should be handled in its own catch clause.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter
+ /following-sibling::Block//InstanceOfExpression/PrimaryExpression/PrimaryPrefix
+  /Name[
+   @Image = ./ancestor::Block/preceding-sibling::FormalParameter
+    /VariableDeclaratorId/@Name
+  ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+try { // Avoid this
+    // do something
+} catch (Exception ee) {
+    if (ee instanceof IOException) {
+        cleanup();
+    }
+}
+
+try {  // Prefer this:
+    // do something
+} catch (IOException ee) {
+    cleanup();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLiteralsInIfCondition"
+          language="java"
+          since="4.2.6"
+          message="Avoid using Literals in Conditional Statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidliteralsinifcondition">
+        <description>
+            Avoid using hard-coded literals in conditional statements. By declaring them as static variables
+            or private members with descriptive names maintainability is enhanced. By default, the literals "-1" and "0" are ignored.
+            More exceptions can be defined with the property "ignoreMagicNumbers".
+
+            The rule doesn't consider deeper expressions by default, but this can be enabled via the property `ignoreExpressions`.
+            With this property set to false, if-conditions like `i == 1 + 5` are reported as well. Note that in that case,
+            the property ignoreMagicNumbers is not taken into account, if there are multiple literals involved in such an expression.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="ignoreMagicNumbers"
+                      description="Comma-separated list of magic numbers, that should be ignored"
+                      type="String" value="-1,0"/>
+            <property name="ignoreExpressions"
+                      description="If true, only literals in simple if conditions are considered. Otherwise literals in expressions are checked, too."
+                      type="Boolean" value="true"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(: simple case - no deep expressions :)
+//IfStatement[$ignoreExpressions = true()]/Expression/*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider also deeper expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression//*[local-name() != 'UnaryExpression' or @Operator != '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider negative literals :)
+//IfStatement[$ignoreExpressions = false()]/Expression//UnaryExpression[@Operator = '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), concat('-', @Image)))]
+|
+(: consider multiple literals in expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression[count(*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]) > 1]
+]]>
+                </value>
+            </property>
+            <property name="version" value="2.0"/>
+        </properties>
+        <example>
+            <![CDATA[
+private static final int MAX_NUMBER_OF_REQUESTS = 10;
+
+public void checkRequests() {
+
+    if (i == 10) {                        // magic number, buried in a method
+      doSomething();
+    }
+
+    if (i == MAX_NUMBER_OF_REQUESTS) {    // preferred approach
+      doSomething();
+    }
+
+    if (aString.indexOf('.') != -1) {}     // magic number -1, by default ignored
+    if (aString.indexOf('.') >= 0) { }     // alternative approach
+
+    if (aDouble > 0.0) {}                  // magic number 0.0
+    if (aDouble >= Double.MIN_VALUE) {}    // preferred approach
+
+    // with rule property "ignoreExpressions" set to "false"
+    if (i == pos + 5) {}  // violation: magic number 5 within an (additive) expression
+    if (i == pos + SUFFIX_LENGTH) {} // preferred approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLosingExceptionInformation"
+          since="4.2.6"
+          language="java"
+          message="Avoid statements in a catch block that invoke accessors on the exception without using the information"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidlosingexceptioninformation">
+        <description>
+            Statements in a catch block that invoke accessors on the exception without using the information
+            only add to code size.  Either remove the invocation, or use the return result.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/Block/BlockStatement/Statement/StatementExpression/PrimaryExpression/PrimaryPrefix/Name
+[
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getLocalizedMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getCause')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getStackTrace')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.toString')
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (SomeException se) {
+        se.getMessage();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidMultipleUnaryOperators"
+          language="java"
+          since="4.2"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidMultipleUnaryOperatorsRule"
+          message="Using multiple unary operators may be a bug, and/or is confusing."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidmultipleunaryoperators">
+        <description>
+            The use of multiple unary operators may be problematic, and/or confusing.
+            Ensure that the intended usage is not a bug, or consider simplifying the expression.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// These are typo bugs, or at best needlessly complex and confusing:
+int i = - -1;
+int j = + - +1;
+int z = ~~2;
+boolean b = !!true;
+boolean c = !!!true;
+
+// These are better:
+int i = 1;
+int j = -1;
+int z = 2;
+boolean b = true;
+boolean c = false;
+
+// And these just make your brain hurt:
+int i = ~-2;
+int j = -~7;
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidUsingOctalValues"
+          language="java"
+          since="3.9"
+          message="Do not start a literal by 0 unless it's an octal value"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidUsingOctalValuesRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidusingoctalvalues">
+        <description>
+            Integer literals should not start with zero since this denotes that the rest of literal will be
+            interpreted as an octal value.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+int i = 012;    // set i with 10 not 12
+int j = 010;    // set j with 8 not 10
+k = i * j;      // set k with 80 not 120
+]]>
+        </example>
+    </rule>
+
+    <rule name="BadComparison" ref="ComparisonWithNaN" deprecated="true" />
+
+    <rule name="BeanMembersShouldSerialize"
+          language="java"
+          since="1.1"
+          message="Found non-transient, non-static member. Please mark as transient or provide accessors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BeanMembersShouldSerializeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#beanmembersshouldserialize">
+        <description>
+            If a class is a bean, or is referenced by a bean directly or indirectly it needs to be serializable.
+            Member variables need to be marked as transient, static, or have accessor methods in the class. Marking
+            variables as transient is the safest and easiest modification. Accessor methods should follow the Java
+            naming conventions, i.e. for a variable named foo, getFoo() and setFoo() accessor methods should be provided.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private transient int someFoo;  // good, it's transient
+private static int otherFoo;    // also OK
+private int moreFoo;            // OK, has proper accessors, see below
+private int badFoo;             // bad, should be marked transient
+
+private void setMoreFoo(int moreFoo){
+      this.moreFoo = moreFoo;
+}
+
+private int getMoreFoo(){
+      return this.moreFoo;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="BrokenNullCheck"

Review comment:
       This rule is enabled in our repo 

##########
File path: check-rules/errorprone.xml
##########
@@ -0,0 +1,3721 @@
+<?xml version="1.0"?>
+
+<ruleset name="Error Prone"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+    <description>
+        Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
+    </description>
+
+    <rule name="AssignmentInOperand"
+          language="java"
+          since="1.03"
+          message="Avoid assignments in operands"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentInOperandRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmentinoperand">
+        <description>
+            Avoid assignments in operands; this can make code more complicated and harder to read.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    if ((x = getX()) == 3) {
+      System.out.println("3!");
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AssignmentToNonFinalStatic"
+          language="java"
+          since="2.2"
+          message="Possible unsafe assignment to a non-final static field in a constructor."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentToNonFinalStaticRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmenttononfinalstatic">
+        <description>
+            Identifies a possible unsafe usage of a static field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class StaticField {
+   static int x;
+   public FinalFields(int y) {
+    x = y; // unsafe
+   }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAccessibilityAlteration"
+          language="java"
+          since="4.1"
+          message="You should not modify visibility of class or methods using getDeclaredConstructors(), getDeclaredConstructor(Class[]), setAccessible() or PrivilegedAction."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidaccessibilityalteration">
+        <description>
+            Methods such as getDeclaredConstructors(), getDeclaredConstructor(Class[]) and setAccessible(),
+            as the interface PrivilegedAction, allow for the runtime alteration of variable, class, or
+            method visibility, even if they are private. This violates the principle of encapsulation.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimaryExpression[
+(
+(PrimarySuffix[
+        ends-with(@Image,'getDeclaredConstructors')
+                or
+        ends-with(@Image,'getDeclaredConstructor')
+                or
+        ends-with(@Image,'setAccessible')
+        ])
+or
+(PrimaryPrefix/Name[
+        ends-with(@Image,'getDeclaredConstructor')
+        or
+        ends-with(@Image,'getDeclaredConstructors')
+        or
+        starts-with(@Image,'AccessibleObject.setAccessible')
+        ])
+)
+and
+(//ImportDeclaration/Name[
+        contains(@Image,'java.security.PrivilegedAction')])
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+
+public class Violation {
+  public void invalidCallsInMethod() throws SecurityException, NoSuchMethodException {
+    // Possible call to forbidden getDeclaredConstructors
+    Class[] arrayOfClass = new Class[1];
+    this.getClass().getDeclaredConstructors();
+    this.getClass().getDeclaredConstructor(arrayOfClass);
+    Class clazz = this.getClass();
+    clazz.getDeclaredConstructor(arrayOfClass);
+    clazz.getDeclaredConstructors();
+      // Possible call to forbidden setAccessible
+    clazz.getMethod("", arrayOfClass).setAccessible(false);
+    AccessibleObject.setAccessible(null, false);
+    Method.setAccessible(null, false);
+    Method[] methodsArray = clazz.getMethods();
+    int nbMethod;
+    for ( nbMethod = 0; nbMethod < methodsArray.length; nbMethod++ ) {
+      methodsArray[nbMethod].setAccessible(false);
+    }
+
+      // Possible call to forbidden PrivilegedAction
+    PrivilegedAction priv = (PrivilegedAction) new Object(); priv.run();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAssertAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using assert as an identifier; it became a reserved word in JDK 1.4"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidassertasidentifier">
+        <description>
+            Use of the term 'assert' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='assert']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String assert = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidBranchingStatementAsLastInLoop"
+          language="java"
+          since="5.0"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidBranchingStatementAsLastInLoopRule"
+          message="Avoid using a branching statement as the last in a loop."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidbranchingstatementaslastinloop">
+        <description>
+            Using a branching statement as the last part of a loop may be a bug, and/or is confusing.
+            Ensure that the usage is not a bug, or consider using another approach.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// unusual use of branching statement in a loop
+for (int i = 0; i < 10; i++) {
+    if (i*i <= 25) {
+        continue;
+    }
+    break;
+}
+
+// this makes more sense...
+for (int i = 0; i < 10; i++) {
+    if (i*i > 25) {
+        break;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCallingFinalize"
+          language="java"
+          since="3.0"
+          message="Avoid calling finalize() explicitly"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCallingFinalizeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcallingfinalize">
+        <description>
+            The method Object.finalize() is called by the garbage collector on an object when garbage collection determines
+            that there are no more references to the object. It should not be invoked by application logic.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+void foo() {
+    Bar b = new Bar();
+    b.finalize();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingNPE"
+          language="java"
+          since="1.8"
+          message="Avoid catching NullPointerException; consider removing the cause of the NPE."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingnpe">
+        <description>
+            Code should never throw NullPointerExceptions under normal circumstances.  A catch block may hide the
+            original error, causing other, more subtle problems later on.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter/Type
+ /ReferenceType/ClassOrInterfaceType[@Image='NullPointerException']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    void bar() {
+        try {
+            // do something
+        } catch (NullPointerException npe) {
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingThrowable"
+          language="java"
+          since="1.2"
+          message="A catch statement should never catch throwable since it includes errors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCatchingThrowableRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingthrowable">
+        <description>
+            Catching Throwable errors is not recommended since its scope is very broad. It includes runtime issues such as
+            OutOfMemoryError that should be exposed and managed separately.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (Throwable th) {  // should not catch Throwable
+        th.printStackTrace();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDecimalLiteralsInBigDecimalConstructor"
+          language="java"
+          since="3.4"
+          message="Avoid creating BigDecimal with a decimal (float/double) literal. Use a String literal"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoiddecimalliteralsinbigdecimalconstructor">
+        <description>
+            One might assume that the result of "new BigDecimal(0.1)" is exactly equal to 0.1, but it is actually
+            equal to .1000000000000000055511151231257827021181583404541015625.
+            This is because 0.1 cannot be represented exactly as a double (or as a binary fraction of any finite
+            length). Thus, the long value that is being passed in to the constructor is not exactly equal to 0.1,
+            appearances notwithstanding.
+
+            The (String) constructor, on the other hand, is perfectly predictable: 'new BigDecimal("0.1")' is
+            exactly equal to 0.1, as one would expect.  Therefore, it is generally recommended that the
+            (String) constructor be used in preference to this one.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//AllocationExpression[pmd-java:typeIs('java.math.BigDecimal')]
+[Arguments/ArgumentList/Expression/PrimaryExpression
+    [
+        pmd-java:typeIs('float') or
+        pmd-java:typeIs('java.lang.Float') or
+        pmd-java:typeIs('double') or
+        pmd-java:typeIs('java.lang.Double')
+    ]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+BigDecimal bd = new BigDecimal(1.123);       // loss of precision, this would trigger the rule
+
+BigDecimal bd = new BigDecimal("1.123");     // preferred approach
+
+BigDecimal bd = new BigDecimal(12);          // preferred approach, ok for integer values
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDuplicateLiterals"
+          language="java"
+          since="1.0"
+          message="The String literal {0} appears {1} times in this file; the first occurrence is on line {2}"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidDuplicateLiteralsRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidduplicateliterals">
+        <description>
+            Code containing duplicate String literals can usually be improved by declaring the String as a constant field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private void bar() {
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+}
+private void buz(String x) {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidEnumAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using enum as an identifier; it's a reserved word in JDK 1.5"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidenumasidentifier">
+        <description>
+            Use of the term 'enum' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='enum']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String enum = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingMethodName"
+          language="java"
+          since="3.0"
+          message="Field {0} has the same name as a method"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingMethodNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingmethodname">
+        <description>
+            It can be confusing to have a field name with the same name as a method. While this is permitted,
+            having information (field) and actions (method) is not clear naming. Developers versed in
+            Smalltalk often prefer this approach as the methods denote accessor methods.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+    Object bar;
+    // bar is data or an action or both?
+    void bar() {
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingTypeName"
+          language="java"
+          since="3.0"
+          message="It is somewhat confusing to have a field name matching the declaring class name"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingTypeNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingtypename">
+        <description>
+            It is somewhat confusing to have a field name matching the declaring type name.
+            This probably means that type and/or field names should be chosen more carefully.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo extends Bar {
+    int foo;    // There is probably a better name that can be used
+}
+public interface Operation {
+    int OPERATION = 1; // There is probably a better name that can be used
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidInstanceofChecksInCatchClause"
+          language="java"
+          since="3.0"
+          message="An instanceof check is being performed on the caught exception.  Create a separate catch clause for this exception type."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidinstanceofchecksincatchclause">
+        <description>
+            Each caught exception type should be handled in its own catch clause.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter
+ /following-sibling::Block//InstanceOfExpression/PrimaryExpression/PrimaryPrefix
+  /Name[
+   @Image = ./ancestor::Block/preceding-sibling::FormalParameter
+    /VariableDeclaratorId/@Name
+  ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+try { // Avoid this
+    // do something
+} catch (Exception ee) {
+    if (ee instanceof IOException) {
+        cleanup();
+    }
+}
+
+try {  // Prefer this:
+    // do something
+} catch (IOException ee) {
+    cleanup();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLiteralsInIfCondition"
+          language="java"
+          since="4.2.6"
+          message="Avoid using Literals in Conditional Statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidliteralsinifcondition">
+        <description>
+            Avoid using hard-coded literals in conditional statements. By declaring them as static variables
+            or private members with descriptive names maintainability is enhanced. By default, the literals "-1" and "0" are ignored.
+            More exceptions can be defined with the property "ignoreMagicNumbers".
+
+            The rule doesn't consider deeper expressions by default, but this can be enabled via the property `ignoreExpressions`.
+            With this property set to false, if-conditions like `i == 1 + 5` are reported as well. Note that in that case,
+            the property ignoreMagicNumbers is not taken into account, if there are multiple literals involved in such an expression.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="ignoreMagicNumbers"
+                      description="Comma-separated list of magic numbers, that should be ignored"
+                      type="String" value="-1,0"/>
+            <property name="ignoreExpressions"
+                      description="If true, only literals in simple if conditions are considered. Otherwise literals in expressions are checked, too."
+                      type="Boolean" value="true"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(: simple case - no deep expressions :)
+//IfStatement[$ignoreExpressions = true()]/Expression/*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider also deeper expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression//*[local-name() != 'UnaryExpression' or @Operator != '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider negative literals :)
+//IfStatement[$ignoreExpressions = false()]/Expression//UnaryExpression[@Operator = '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), concat('-', @Image)))]
+|
+(: consider multiple literals in expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression[count(*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]) > 1]
+]]>
+                </value>
+            </property>
+            <property name="version" value="2.0"/>
+        </properties>
+        <example>
+            <![CDATA[
+private static final int MAX_NUMBER_OF_REQUESTS = 10;
+
+public void checkRequests() {
+
+    if (i == 10) {                        // magic number, buried in a method
+      doSomething();
+    }
+
+    if (i == MAX_NUMBER_OF_REQUESTS) {    // preferred approach
+      doSomething();
+    }
+
+    if (aString.indexOf('.') != -1) {}     // magic number -1, by default ignored
+    if (aString.indexOf('.') >= 0) { }     // alternative approach
+
+    if (aDouble > 0.0) {}                  // magic number 0.0
+    if (aDouble >= Double.MIN_VALUE) {}    // preferred approach
+
+    // with rule property "ignoreExpressions" set to "false"
+    if (i == pos + 5) {}  // violation: magic number 5 within an (additive) expression
+    if (i == pos + SUFFIX_LENGTH) {} // preferred approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLosingExceptionInformation"
+          since="4.2.6"
+          language="java"
+          message="Avoid statements in a catch block that invoke accessors on the exception without using the information"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidlosingexceptioninformation">
+        <description>
+            Statements in a catch block that invoke accessors on the exception without using the information
+            only add to code size.  Either remove the invocation, or use the return result.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/Block/BlockStatement/Statement/StatementExpression/PrimaryExpression/PrimaryPrefix/Name
+[
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getLocalizedMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getCause')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getStackTrace')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.toString')
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (SomeException se) {
+        se.getMessage();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidMultipleUnaryOperators"
+          language="java"
+          since="4.2"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidMultipleUnaryOperatorsRule"
+          message="Using multiple unary operators may be a bug, and/or is confusing."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidmultipleunaryoperators">
+        <description>
+            The use of multiple unary operators may be problematic, and/or confusing.
+            Ensure that the intended usage is not a bug, or consider simplifying the expression.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// These are typo bugs, or at best needlessly complex and confusing:
+int i = - -1;
+int j = + - +1;
+int z = ~~2;
+boolean b = !!true;
+boolean c = !!!true;
+
+// These are better:
+int i = 1;
+int j = -1;
+int z = 2;
+boolean b = true;
+boolean c = false;
+
+// And these just make your brain hurt:
+int i = ~-2;
+int j = -~7;
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidUsingOctalValues"
+          language="java"
+          since="3.9"
+          message="Do not start a literal by 0 unless it's an octal value"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidUsingOctalValuesRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidusingoctalvalues">
+        <description>
+            Integer literals should not start with zero since this denotes that the rest of literal will be
+            interpreted as an octal value.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+int i = 012;    // set i with 10 not 12
+int j = 010;    // set j with 8 not 10
+k = i * j;      // set k with 80 not 120
+]]>
+        </example>
+    </rule>
+
+    <rule name="BadComparison" ref="ComparisonWithNaN" deprecated="true" />
+
+    <rule name="BeanMembersShouldSerialize"
+          language="java"
+          since="1.1"
+          message="Found non-transient, non-static member. Please mark as transient or provide accessors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BeanMembersShouldSerializeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#beanmembersshouldserialize">
+        <description>
+            If a class is a bean, or is referenced by a bean directly or indirectly it needs to be serializable.
+            Member variables need to be marked as transient, static, or have accessor methods in the class. Marking
+            variables as transient is the safest and easiest modification. Accessor methods should follow the Java
+            naming conventions, i.e. for a variable named foo, getFoo() and setFoo() accessor methods should be provided.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private transient int someFoo;  // good, it's transient
+private static int otherFoo;    // also OK
+private int moreFoo;            // OK, has proper accessors, see below
+private int badFoo;             // bad, should be marked transient
+
+private void setMoreFoo(int moreFoo){
+      this.moreFoo = moreFoo;
+}
+
+private int getMoreFoo(){
+      return this.moreFoo;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="BrokenNullCheck"
+          language="java"
+          since="3.8"
+          message="Method call on object which may be null"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BrokenNullCheckRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#brokennullcheck">
+        <description>
+            The null check is broken since it will throw a NullPointerException itself.
+            It is likely that you used || instead of &amp;&amp; or vice versa.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+public String bar(String string) {
+  // should be &&
+    if (string!=null || !string.equals(""))
+        return string;
+  // should be ||
+    if (string==null && string.equals(""))
+        return string;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperFirst"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the start of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperfirst">
+        <description>Super should be called at the start of the method</description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='onCreate' or
+  @Name='onConfigurationChanged' or
+  @Name='onPostCreate' or
+  @Name='onPostResume' or
+  @Name='onRestart' or
+  @Name='onRestoreInstanceState' or
+  @Name='onResume' or
+  @Name='onStart'
+  ]
+    /Block[not(
+      (BlockStatement[1]/Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name]))]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onCreate(Bundle bundle) {
+        // missing call to super.onCreate(bundle)
+        foo();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperLast"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the end of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperlast">
+        <description>
+            Super should be called at the end of the method
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='finish' or
+  @Name='onDestroy' or
+  @Name='onPause' or
+  @Name='onSaveInstanceState' or
+  @Name='onStop' or
+  @Name='onTerminate'
+  ]
+   /Block/BlockStatement[last()]
+    [not(Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name])]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onPause() {
+        foo();
+        // missing call to super.onPause()
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CheckSkipResult"
+          language="java"
+          since="5.0"
+          message="Check the value returned by the skip() method of an InputStream to see if the requested number of bytes has been skipped."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CheckSkipResultRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#checkskipresult">
+        <description>
+            The skip() method may skip a smaller number of bytes than requested. Check the returned value to find out if it was the case or not.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private FileInputStream _s = new FileInputStream("file");
+
+   public void skip(int n) throws IOException {
+      _s.skip(n); // You are not sure that exactly n bytes are skipped
+   }
+
+   public void skipExactly(int n) throws IOException {
+      while (n != 0) {
+         long skipped = _s.skip(n);
+         if (skipped == 0)
+            throw new EOFException();
+         n -= skipped;
+      }
+   }
+]]>
+        </example>
+    </rule>
+
+    <rule name="ClassCastExceptionWithToArray"
+          language="java"
+          since="3.4"
+          message="This usage of the Collection.toArray() method will throw a ClassCastException."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#classcastexceptionwithtoarray">
+        <description>
+            When deriving an array of a specific class from your Collection, one should provide an array of
+            the same class as the parameter of the toArray() method. Doing otherwise you will will result
+            in a ClassCastException.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CastExpression[Type/ReferenceType/ClassOrInterfaceType[@Image != "Object"]]
+    /PrimaryExpression
+    [PrimaryPrefix/Name[ends-with(@Image, '.toArray')]]
+    [PrimarySuffix/Arguments[not(*)]]
+    [count(PrimarySuffix) = 1]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+Collection c = new ArrayList();
+Integer obj = new Integer(1);
+c.add(obj);
+
+    // this would trigger the rule (and throw a ClassCastException if executed)
+Integer[] a = (Integer [])c.toArray();
+
+   // this is fine and will not trigger the rule
+Integer[] b = (Integer [])c.toArray(new Integer[c.size()]);
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustBePublic"
+          language="java"
+          since="5.4.0"
+          message="clone() method must be public if the class implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustbepublic">
+        <description>
+            The java Manual says "By convention, classes that implement this interface should override
+            Object.clone (which is protected) with a public method."
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Public= false()]
+  [@Name = 'clone']
+  [@Arity = 0]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() throws CloneNotSupportedException { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    protected Foo clone() { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Object clone() // Ok
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustImplementCloneable"
+          language="java"
+          since="1.9"
+          message="clone() method should be implemented only if implementing Cloneable interface"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloneMethodMustImplementCloneableRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustimplementcloneable">
+        <description>
+            The method clone() should only be implemented if the class implements the Cloneable interface with the exception of
+            a final method that only throws CloneNotSupportedException.
+
+            The rule can also detect, if the class implements or extends a Cloneable class.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class MyClass {
+ public Object clone() throws CloneNotSupportedException {
+  return foo;
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodReturnTypeMustMatchClassName"
+          language="java"
+          minimumLanguageVersion="1.5"
+          since="5.4.0"
+          message="The return type of the clone() method must be the class name when implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodreturntypemustmatchclassname">
+        <description>
+            If a class implements cloneable the return type of the method clone() must be the class name. That way, the caller
+            of the clone method doesn't need to cast the returned clone to the correct type.
+
+            Note: This is only possible with Java 1.5 or higher.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and not (ResultType//ClassOrInterfaceType/@Image = ancestor::ClassOrInterfaceDeclaration[1]/@SimpleName)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() { // Violation, Object must be Foo
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Foo clone() { //Ok
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneThrowsCloneNotSupportedException"
+          deprecated="true"
+          language="java"
+          since="1.9"
+          message="clone() method should throw CloneNotSupportedException"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonethrowsclonenotsupportedexception">
+        <description>
+            The method clone() should throw a CloneNotSupportedException.
+
+            This rule is deprecated since PMD 6.35.0 without replacement. The rule has no real value as
+            `CloneNotSupportedException` is a checked exception and therefore you need to deal with it while
+            implementing the `clone()` method. You either need to declare the exception or catch it. If you catch it,
+            then subclasses can't throw it themselves explicitly. However, `Object.clone()` will still throw this
+            exception if the `Cloneable` interface is not implemented.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and count(NameList/Name[contains
+(@Image,'CloneNotSupportedException')]) = 0
+]
+[
+../../../../ClassOrInterfaceDeclaration[@Final = false()]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyClass implements Cloneable{
+    public Object clone() { // will cause an error
+         MyClass clone = (MyClass)super.clone();
+         return clone;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloseResource"
+          language="java"
+          since="1.2.2"
+          message="Ensure that resources like this {0} object are closed after use"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloseResourceRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#closeresource">
+        <description>
+            Ensure that resources (like `java.sql.Connection`, `java.sql.Statement`, and `java.sql.ResultSet` objects
+            and any subtype of `java.lang.AutoCloseable`) are always closed after use.
+            Failing to do so might result in resource leaks.
+
+            Note: It suffices to configure the super type, e.g. `java.lang.AutoClosable`, so that this rule automatically triggers
+            on any subtype (e.g. `java.io.FileInputStream`). Additionally specifying `java.sql.Connection` helps in detecting
+            the types, if the type resolution / auxclasspath is not correctly setup.
+
+            Note: Since PMD 6.16.0 the default value for the property `types` contains `java.lang.AutoCloseable` and detects
+            now cases where the standard `java.io.*Stream` classes are involved. In order to restore the old behaviour,
+            just remove "AutoCloseable" from the types.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Bar {
+    public void withSQL() {
+        Connection c = pool.getConnection();
+        try {
+            // do stuff
+        } catch (SQLException ex) {
+           // handle exception
+        } finally {
+            // oops, should close the connection using 'close'!
+            // c.close();
+        }
+    }
+
+    public void withFile() {
+        InputStream file = new FileInputStream(new File("/tmp/foo"));
+        try {
+            int c = file.in();
+        } catch (IOException e) {
+            // handle exception
+        } finally {
+            // TODO: close file
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CompareObjectsWithEquals"
+          language="java"
+          since="3.2"
+          message="Use equals() to compare object references."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#compareobjectswithequals">
+        <description>
+            Use `equals()` to compare object references; avoid comparing them with `==`.
+
+            Since comparing objects with named constants is useful in some cases (eg, when
+            defining constants for sentinel values), the rule ignores comparisons against
+            fields with all-caps name (eg `this == SENTINEL`), which is a common naming
+            convention for constant fields.
+
+            You may allow some types to be compared by reference by listing the exceptions
+            in the `typesThatCompareByReference` property.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="typesThatCompareByReference" type="List[String]" delimiter="," description="List of canonical type names for which reference comparison is allowed.">
+                <value>java.lang.Enum,java.lang.Class</value>
+            </property>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EqualityExpression
+    [count(
+        PrimaryExpression[pmd-java:typeIs('java.lang.Object')]
+        [not(some $t in $typesThatCompareByReference satisfies pmd-java:typeIs($t))]
+       ) = 2
+    ]
+    [not(PrimaryExpression[PrimaryPrefix/@ThisModifier = true()]
+                          [not(PrimarySuffix)]
+                          [ancestor::MethodDeclaration[@Name = 'equals']])
+    ]
+    (: Is not a field access with an all-caps identifier :)
+    [not(PrimaryExpression[not(PrimarySuffix) and PrimaryPrefix/Name[upper-case(@Image)=@Image]
+     or PrimaryExpression/PrimarySuffix[last()][upper-case(@Image)=@Image]])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+class Foo {
+  boolean bar(String a, String b) {
+    return a == b;
+  }
+}
+
+]]>
+        </example>
+    </rule>
+
+    <rule name="ComparisonWithNaN"
+          language="java"
+          since="6.36.0"
+          message="Comparisons with NaN always return false"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+        <description><![CDATA[
+            Reports comparisons with double and float `NaN` (Not-a-Number) values.
+            These are [specified](https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.21.1)
+            to have unintuitive behavior: NaN is considered unequal to itself.
+            This means a check like `someDouble == Double.NaN` will always return
+            false, even if `someDouble` is really the NaN value. To test whether a
+            value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+            (or `Float.isNaN`). The `!=` operator should be treated similarly.
+            Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+            and will always evaluate to false.
+
+            This rule has been renamed from "BadComparison" with PMD 6.36.0.
+        ]]></description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+        </example>
+    </rule>
+
+
+    <rule name="ConstructorCallsOverridableMethod"
+          language="java"
+          since="1.04"
+          message="Overridable {0} called during object construction"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#constructorcallsoverridablemethod">
+        <description>
+            Calling overridable methods during construction poses a risk of invoking methods on an incompletely
+            constructed object and can be difficult to debug.
+            It may leave the sub-class unable to construct its superclass or forced to replicate the construction
+            process completely within itself, losing the ability to call super().  If the default constructor
+            contains a call to an overridable method, the subclass may be completely uninstantiable.   Note that
+            this includes method calls throughout the control flow graph - i.e., if a constructor Foo() calls a
+            private method bar() that calls a public method buz(), this denotes a problem.
+        </description>
+        <priority>1</priority>
+        <example>
+            <![CDATA[
+public class SeniorClass {
+  public SeniorClass(){
+      toString(); //may throw NullPointerException if overridden
+  }
+  public String toString(){
+    return "IAmSeniorClass";
+  }
+}
+public class JuniorClass extends SeniorClass {
+  private String name;
+  public JuniorClass(){
+    super(); //Automatic call leads to NullPointerException
+    name = "JuniorClass";
+  }
+  public String toString(){
+    return name.toUpperCase();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DataflowAnomalyAnalysis"
+          language="java"
+          since="3.9"
+          message="Found ''{0}''-anomaly for variable ''{1}'' (lines ''{2}''-''{3}'')."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DataflowAnomalyAnalysisRule"
+          dfa="true"
+          deprecated="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dataflowanomalyanalysis">
+        <description>The dataflow analysis tracks local definitions, undefinitions and references to variables on different paths on the data flow.
+            From those informations there can be found various problems.
+
+            1. DU - Anomaly: A recently defined variable is undefined. These anomalies may appear in normal source text.
+            2. DD - Anomaly: A recently defined variable is redefined. This is ominous but don't have to be a bug.
+
+            This rule is deprecated. Use {% rule "java/bestpractices/UnusedAssignment" %} in category bestpractices instead.
+        </description>
+        <priority>5</priority>
+        <example>
+            <![CDATA[
+public void foo() {
+  int buz = 5;
+  buz = 6; // redefinition of buz -> dd-anomaly
+  foo(buz);
+  buz = 2;
+} // buz is undefined when leaving scope -> du-anomaly
+]]>
+        </example>
+    </rule>
+
+    <rule name="DetachedTestCase"
+          language="java"
+          since="6.13.0"
+          message="Probable detached JUnit test case."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#detachedtestcase">
+        <description>
+            The method appears to be a test case since it has public or default visibility,
+            non-static access, no arguments, no return value, has no annotations, but is a
+            member of a class that has one or more JUnit test cases. If it is a utility
+            method, it should likely have private visibility. If it is an ignored test, it
+            should be annotated with @Test and @Ignore.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value><![CDATA[
+//ClassOrInterfaceBodyDeclaration
+[../ClassOrInterfaceBodyDeclaration/Annotation/*/Name
+        [pmd-java:typeIs('org.junit.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestFactory')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
+         or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')]
+]
+[not(Annotation)]
+[MethodDeclaration[(@Public = true() or @PackagePrivate = true()) and @Static = false() and
+        ResultType[@Void = true()] and
+        MethodDeclarator/FormalParameters[@Size = 0]
+    ]
+]
+]]></value>
+            </property>
+            <property name="version" value="2.0" />
+        </properties>
+        <example>
+            <![CDATA[
+public class MyTest {
+    @Test
+    public void someTest() {
+    }
+
+    // violation: Not annotated
+    public void someOtherTest () {
+    }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallGarbageCollectionExplicitly"
+          language="java"
+          since="4.2"
+          message="Do not explicitly trigger a garbage collection."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotcallgarbagecollectionexplicitly">
+        <description>
+            Calls to System.gc(), Runtime.getRuntime().gc(), and System.runFinalization() are not advised. Code should have the
+            same behavior whether the garbage collection is disabled using the option -Xdisableexplicitgc or not.
+            Moreover, "modern" jvms do a very good job handling garbage collections. If memory usage issues unrelated to memory
+            leaks develop within an application, it should be dealt with JVM options rather than within the code itself.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+(starts-with(@Image, 'System.') and
+(starts-with(@Image, 'System.gc') or
+starts-with(@Image, 'System.runFinalization'))) or
+(
+starts-with(@Image,'Runtime.getRuntime') and
+../../PrimarySuffix[ends-with(@Image,'gc')]
+)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class GCCall {
+    public GCCall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+
+    public explicitGCcall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallSystemExit" ref="category/java/errorprone.xml/DoNotTerminateVM" deprecated="true" />
+
+    <rule name="DoNotExtendJavaLangThrowable"
+          language="java"
+          since="6.0.0"
+          message="Exceptions should not extend java.lang.Throwable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotextendjavalangthrowable">
+        <description>
+            Extend Exception or RuntimeException instead of Throwable.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration/ExtendsList/ClassOrInterfaceType
+  [@Image="Throwable" or @Image="java.lang.Throwable"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo extends Throwable { }
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotHardCodeSDCard"
+          since="4.2.6"
+          language="java"
+          message="Do not hardcode /sdcard."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donothardcodesdcard">
+        <description>
+            Use Environment.getExternalStorageDirectory() instead of "/sdcard"
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Literal[starts-with(@Image,'"/sdcard')]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyActivity extends Activity {
+    protected void foo() {
+        String storageLocation = "/sdcard/mypackage";   // hard-coded, poor approach
+
+       storageLocation = Environment.getExternalStorageDirectory() + "/mypackage"; // preferred approach
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotTerminateVM"
+          language="java"
+          since="4.1"
+          message="System.exit() should not be used in J2EE/JEE apps"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotterminatevm">
+        <description>
+            Web applications should not call `System.exit()`, since only the web container or the
+            application server should stop the JVM. Otherwise a web application would terminate all other applications
+            running on the same application server.
+
+            This rule also checks for the equivalent calls `Runtime.getRuntime().exit()` and `Runtime.getRuntime().halt()`.
+
+            This rule was called *DoNotCallSystemExit* until PMD 6.29.0.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+    starts-with(@Image,'System.exit')
+    or
+    (starts-with(@Image,'Runtime.getRuntime') and ../../PrimarySuffix[ends-with(@Image,'exit') or ends-with(@Image,'halt')])
+][not(ancestor::MethodDeclaration[1][@Name="main" and @Static = true()])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    System.exit(0);                 // never call this when running in an application server!
+}
+public void foo() {
+    Runtime.getRuntime().exit(0);   // never stop the JVM manually, the container will do this.
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotThrowExceptionInFinally"
+          language="java"
+          since="4.2"
+          message="A throw statement in a finally block makes the control flow hard to understand."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotthrowexceptioninfinally">
+        <description>
+            Throwing exceptions within a 'finally' block is confusing since they may mask other exceptions
+            or code defects.
+            Note: This is a PMD implementation of the Lint4j rule "A throw in a finally block"
+        </description>
+        <priority>4</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//FinallyStatement[descendant::ThrowStatement]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            // Here do some stuff
+        } catch( Exception e) {
+            // Handling the issue
+        } finally {
+            // is this really a good idea ?
+            throw new Exception();
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontImportSun"
+          language="java"
+          since="1.5"
+          message="Avoid importing anything from the 'sun.*' packages"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DontImportSunRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontimportsun">
+        <description>
+            Avoid importing anything from the 'sun.*' packages.  These packages are not portable and are likely to change.
+        </description>
+        <priority>4</priority>
+        <example>
+            <![CDATA[
+import sun.misc.foo;
+public class Foo {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontUseFloatTypeForLoopIndices"
+          language="java"
+          since="4.3"
+          message="Don't use floating point for loop indices. If you must use floating point, use double."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontusefloattypeforloopindices">
+        <description>
+            Don't use floating point for loop indices. If you must use floating point, use double
+            unless you're certain that float provides enough precision and you have a compelling
+            performance need (space or time).
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ForStatement/ForInit/LocalVariableDeclaration
+/Type/PrimitiveType[@Image="float"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Count {
+  public static void main(String[] args) {
+    final int START = 2000000000;
+    int count = 0;
+    for (float f = START; f < START + 50; f++)
+      count++;
+      //Prints 0 because (float) START == (float) (START + 50).
+      System.out.println(count);
+      //The termination test misbehaves due to floating point granularity.
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyCatchBlock"
+          language="java"
+          since="0.1"
+          message="Avoid empty catch blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptycatchblock">
+        <description>
+            Empty Catch Block finds instances where an exception is caught, but nothing is done.
+            In most circumstances, this swallows an exception which should either be acted on
+            or reported.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement
+ [not(Block/BlockStatement)]
+ [$allowCommentedBlocks != true() or Block/@containsComment = false()]
+ [FormalParameter/Type/ReferenceType
+   /ClassOrInterfaceType[@Image != 'InterruptedException' and @Image != 'CloneNotSupportedException']
+ ]
+ [FormalParameter/VariableDeclaratorId[not(matches(@Name, $allowExceptionNameRegex))]]
+]]>
+                </value>
+            </property>
+            <property name="allowCommentedBlocks" type="Boolean" description="Empty blocks containing comments will be skipped" value="false"/>
+            <property name="allowExceptionNameRegex" type="String" description="Empty blocks catching exceptions with names matching this regular expression will be skipped" value="^(ignored|expected)$"/>
+        </properties>
+        <example>
+            <![CDATA[
+public void doSomething() {
+    try {
+        FileInputStream fis = new FileInputStream("/tmp/bugger");
+    } catch (IOException ioe) {
+        // not good
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinalizer"
+          language="java"
+          since="1.5"
+          message="Avoid empty finalize methods"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinalizer">
+        <description>
+            Empty finalize methods serve no purpose and should be removed. Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Name='finalize'][@Arity = 0]
+  /Block[not(*)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+   protected void finalize() {}
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinallyBlock"
+          language="java"
+          since="0.4"
+          message="Avoid empty finally blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinallyblock">
+        <description>
+            Empty finally blocks serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//FinallyStatement[not(Block/BlockStatement)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            int x=2;
+        } finally {
+            // empty!
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyIfStmt"
+          language="java"
+          since="0.1"
+          message="Avoid empty 'if' statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyifstmt">
+        <description>
+            Empty If Statement finds instances where a condition is checked but nothing is done about it.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//IfStatement/Statement
+ [EmptyStatement or Block[not(*)]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+ void bar(int x) {
+  if (x == 0) {
+   // empty!
+  }
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyInitializer"
+          language="java"
+          since="5.0"
+          message="Empty initializer was found"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyinitializer">
+        <description>
+            Empty initializers serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Initializer/Block[not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   static {} // Why ?
+
+   {} // Again, why ?
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyStatementBlock"
+          language="java"
+          since="5.0"
+          message="Avoid empty block statements."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptystatementblock">
+        <description>
+            Empty block statements serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//BlockStatement/Statement/Block[not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private int _bar;
+
+   public void setBar(int bar) {
+      { _bar = bar; } // Why not?
+      {} // But remove this.
+   }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyStatementNotInLoop"
+          language="java"
+          since="1.5"
+          message="An empty statement (semicolon) not part of a loop"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptystatementnotinloop">
+        <description>
+            An empty statement (or a semicolon by itself) that is not used as the sole body of a 'for'
+            or 'while' loop is probably a bug.  It could also be a double semicolon, which has no purpose
+            and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EmptyStatement
+ [not(
+       ../../../ForStatement
+       or ../../../WhileStatement
+       or ../../../BlockStatement/ClassOrInterfaceDeclaration
+       or ../../../../../../ForStatement/Statement[1]
+        /Block[1]/BlockStatement[1]/Statement/EmptyStatement
+       or ../../../../../../WhileStatement/Statement[1]
+        /Block[1]/BlockStatement[1]/Statement/EmptyStatement)
+ ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void doit() {
+      // this is probably not what you meant to do
+      ;
+      // the extra semicolon here this is not necessary
+      System.out.println("look at the extra semicolon");;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptySwitchStatements"
+          language="java"
+          since="1.0"
+          message="Avoid empty switch statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyswitchstatements">
+        <description>
+            Empty switch statements serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//SwitchStatement[count(*) = 1]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    switch (x) {
+        // once there was code here
+        // but it's been commented out or something
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptySynchronizedBlock"

Review comment:
       This rule is enabled in our repo

##########
File path: check-rules/errorprone.xml
##########
@@ -0,0 +1,3721 @@
+<?xml version="1.0"?>
+
+<ruleset name="Error Prone"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+    <description>
+        Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
+    </description>
+
+    <rule name="AssignmentInOperand"
+          language="java"
+          since="1.03"
+          message="Avoid assignments in operands"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentInOperandRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmentinoperand">
+        <description>
+            Avoid assignments in operands; this can make code more complicated and harder to read.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    if ((x = getX()) == 3) {
+      System.out.println("3!");
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AssignmentToNonFinalStatic"
+          language="java"
+          since="2.2"
+          message="Possible unsafe assignment to a non-final static field in a constructor."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentToNonFinalStaticRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#assignmenttononfinalstatic">
+        <description>
+            Identifies a possible unsafe usage of a static field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class StaticField {
+   static int x;
+   public FinalFields(int y) {
+    x = y; // unsafe
+   }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAccessibilityAlteration"
+          language="java"
+          since="4.1"
+          message="You should not modify visibility of class or methods using getDeclaredConstructors(), getDeclaredConstructor(Class[]), setAccessible() or PrivilegedAction."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidaccessibilityalteration">
+        <description>
+            Methods such as getDeclaredConstructors(), getDeclaredConstructor(Class[]) and setAccessible(),
+            as the interface PrivilegedAction, allow for the runtime alteration of variable, class, or
+            method visibility, even if they are private. This violates the principle of encapsulation.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimaryExpression[
+(
+(PrimarySuffix[
+        ends-with(@Image,'getDeclaredConstructors')
+                or
+        ends-with(@Image,'getDeclaredConstructor')
+                or
+        ends-with(@Image,'setAccessible')
+        ])
+or
+(PrimaryPrefix/Name[
+        ends-with(@Image,'getDeclaredConstructor')
+        or
+        ends-with(@Image,'getDeclaredConstructors')
+        or
+        starts-with(@Image,'AccessibleObject.setAccessible')
+        ])
+)
+and
+(//ImportDeclaration/Name[
+        contains(@Image,'java.security.PrivilegedAction')])
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Method;
+import java.security.PrivilegedAction;
+
+public class Violation {
+  public void invalidCallsInMethod() throws SecurityException, NoSuchMethodException {
+    // Possible call to forbidden getDeclaredConstructors
+    Class[] arrayOfClass = new Class[1];
+    this.getClass().getDeclaredConstructors();
+    this.getClass().getDeclaredConstructor(arrayOfClass);
+    Class clazz = this.getClass();
+    clazz.getDeclaredConstructor(arrayOfClass);
+    clazz.getDeclaredConstructors();
+      // Possible call to forbidden setAccessible
+    clazz.getMethod("", arrayOfClass).setAccessible(false);
+    AccessibleObject.setAccessible(null, false);
+    Method.setAccessible(null, false);
+    Method[] methodsArray = clazz.getMethods();
+    int nbMethod;
+    for ( nbMethod = 0; nbMethod < methodsArray.length; nbMethod++ ) {
+      methodsArray[nbMethod].setAccessible(false);
+    }
+
+      // Possible call to forbidden PrivilegedAction
+    PrivilegedAction priv = (PrivilegedAction) new Object(); priv.run();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidAssertAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using assert as an identifier; it became a reserved word in JDK 1.4"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidassertasidentifier">
+        <description>
+            Use of the term 'assert' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='assert']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String assert = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidBranchingStatementAsLastInLoop"
+          language="java"
+          since="5.0"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidBranchingStatementAsLastInLoopRule"
+          message="Avoid using a branching statement as the last in a loop."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidbranchingstatementaslastinloop">
+        <description>
+            Using a branching statement as the last part of a loop may be a bug, and/or is confusing.
+            Ensure that the usage is not a bug, or consider using another approach.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// unusual use of branching statement in a loop
+for (int i = 0; i < 10; i++) {
+    if (i*i <= 25) {
+        continue;
+    }
+    break;
+}
+
+// this makes more sense...
+for (int i = 0; i < 10; i++) {
+    if (i*i > 25) {
+        break;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCallingFinalize"
+          language="java"
+          since="3.0"
+          message="Avoid calling finalize() explicitly"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCallingFinalizeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcallingfinalize">
+        <description>
+            The method Object.finalize() is called by the garbage collector on an object when garbage collection determines
+            that there are no more references to the object. It should not be invoked by application logic.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+void foo() {
+    Bar b = new Bar();
+    b.finalize();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingNPE"
+          language="java"
+          since="1.8"
+          message="Avoid catching NullPointerException; consider removing the cause of the NPE."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingnpe">
+        <description>
+            Code should never throw NullPointerExceptions under normal circumstances.  A catch block may hide the
+            original error, causing other, more subtle problems later on.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter/Type
+ /ReferenceType/ClassOrInterfaceType[@Image='NullPointerException']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    void bar() {
+        try {
+            // do something
+        } catch (NullPointerException npe) {
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidCatchingThrowable"
+          language="java"
+          since="1.2"
+          message="A catch statement should never catch throwable since it includes errors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidCatchingThrowableRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidcatchingthrowable">
+        <description>
+            Catching Throwable errors is not recommended since its scope is very broad. It includes runtime issues such as
+            OutOfMemoryError that should be exposed and managed separately.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (Throwable th) {  // should not catch Throwable
+        th.printStackTrace();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDecimalLiteralsInBigDecimalConstructor"
+          language="java"
+          since="3.4"
+          message="Avoid creating BigDecimal with a decimal (float/double) literal. Use a String literal"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoiddecimalliteralsinbigdecimalconstructor">
+        <description>
+            One might assume that the result of "new BigDecimal(0.1)" is exactly equal to 0.1, but it is actually
+            equal to .1000000000000000055511151231257827021181583404541015625.
+            This is because 0.1 cannot be represented exactly as a double (or as a binary fraction of any finite
+            length). Thus, the long value that is being passed in to the constructor is not exactly equal to 0.1,
+            appearances notwithstanding.
+
+            The (String) constructor, on the other hand, is perfectly predictable: 'new BigDecimal("0.1")' is
+            exactly equal to 0.1, as one would expect.  Therefore, it is generally recommended that the
+            (String) constructor be used in preference to this one.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//AllocationExpression[pmd-java:typeIs('java.math.BigDecimal')]
+[Arguments/ArgumentList/Expression/PrimaryExpression
+    [
+        pmd-java:typeIs('float') or
+        pmd-java:typeIs('java.lang.Float') or
+        pmd-java:typeIs('double') or
+        pmd-java:typeIs('java.lang.Double')
+    ]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+BigDecimal bd = new BigDecimal(1.123);       // loss of precision, this would trigger the rule
+
+BigDecimal bd = new BigDecimal("1.123");     // preferred approach
+
+BigDecimal bd = new BigDecimal(12);          // preferred approach, ok for integer values
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidDuplicateLiterals"
+          language="java"
+          since="1.0"
+          message="The String literal {0} appears {1} times in this file; the first occurrence is on line {2}"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidDuplicateLiteralsRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidduplicateliterals">
+        <description>
+            Code containing duplicate String literals can usually be improved by declaring the String as a constant field.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private void bar() {
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+     buz("Howdy");
+}
+private void buz(String x) {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidEnumAsIdentifier"
+          language="java"
+          since="3.4"
+          message="Avoid using enum as an identifier; it's a reserved word in JDK 1.5"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidenumasidentifier">
+        <description>
+            Use of the term 'enum' will conflict with newer versions of Java since it is a reserved word.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//VariableDeclaratorId[@Name='enum']</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class A {
+    public class Foo {
+        String enum = "foo";
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingMethodName"
+          language="java"
+          since="3.0"
+          message="Field {0} has the same name as a method"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingMethodNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingmethodname">
+        <description>
+            It can be confusing to have a field name with the same name as a method. While this is permitted,
+            having information (field) and actions (method) is not clear naming. Developers versed in
+            Smalltalk often prefer this approach as the methods denote accessor methods.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+    Object bar;
+    // bar is data or an action or both?
+    void bar() {
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidFieldNameMatchingTypeName"
+          language="java"
+          since="3.0"
+          message="It is somewhat confusing to have a field name matching the declaring class name"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidFieldNameMatchingTypeNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidfieldnamematchingtypename">
+        <description>
+            It is somewhat confusing to have a field name matching the declaring type name.
+            This probably means that type and/or field names should be chosen more carefully.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo extends Bar {
+    int foo;    // There is probably a better name that can be used
+}
+public interface Operation {
+    int OPERATION = 1; // There is probably a better name that can be used
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidInstanceofChecksInCatchClause"
+          language="java"
+          since="3.0"
+          message="An instanceof check is being performed on the caught exception.  Create a separate catch clause for this exception type."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidinstanceofchecksincatchclause">
+        <description>
+            Each caught exception type should be handled in its own catch clause.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/FormalParameter
+ /following-sibling::Block//InstanceOfExpression/PrimaryExpression/PrimaryPrefix
+  /Name[
+   @Image = ./ancestor::Block/preceding-sibling::FormalParameter
+    /VariableDeclaratorId/@Name
+  ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+try { // Avoid this
+    // do something
+} catch (Exception ee) {
+    if (ee instanceof IOException) {
+        cleanup();
+    }
+}
+
+try {  // Prefer this:
+    // do something
+} catch (IOException ee) {
+    cleanup();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLiteralsInIfCondition"
+          language="java"
+          since="4.2.6"
+          message="Avoid using Literals in Conditional Statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidliteralsinifcondition">
+        <description>
+            Avoid using hard-coded literals in conditional statements. By declaring them as static variables
+            or private members with descriptive names maintainability is enhanced. By default, the literals "-1" and "0" are ignored.
+            More exceptions can be defined with the property "ignoreMagicNumbers".
+
+            The rule doesn't consider deeper expressions by default, but this can be enabled via the property `ignoreExpressions`.
+            With this property set to false, if-conditions like `i == 1 + 5` are reported as well. Note that in that case,
+            the property ignoreMagicNumbers is not taken into account, if there are multiple literals involved in such an expression.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="ignoreMagicNumbers"
+                      description="Comma-separated list of magic numbers, that should be ignored"
+                      type="String" value="-1,0"/>
+            <property name="ignoreExpressions"
+                      description="If true, only literals in simple if conditions are considered. Otherwise literals in expressions are checked, too."
+                      type="Boolean" value="true"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(: simple case - no deep expressions :)
+//IfStatement[$ignoreExpressions = true()]/Expression/*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider also deeper expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression//*[local-name() != 'UnaryExpression' or @Operator != '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), @Image))]
+|
+(: consider negative literals :)
+//IfStatement[$ignoreExpressions = false()]/Expression//UnaryExpression[@Operator = '-']/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]
+    [empty(index-of(tokenize($ignoreMagicNumbers, '\s*,\s*'), concat('-', @Image)))]
+|
+(: consider multiple literals in expressions :)
+//IfStatement[$ignoreExpressions = false()]/Expression[count(*/PrimaryExpression/PrimaryPrefix/Literal
+    [not(NullLiteral)]
+    [not(BooleanLiteral)]) > 1]
+]]>
+                </value>
+            </property>
+            <property name="version" value="2.0"/>
+        </properties>
+        <example>
+            <![CDATA[
+private static final int MAX_NUMBER_OF_REQUESTS = 10;
+
+public void checkRequests() {
+
+    if (i == 10) {                        // magic number, buried in a method
+      doSomething();
+    }
+
+    if (i == MAX_NUMBER_OF_REQUESTS) {    // preferred approach
+      doSomething();
+    }
+
+    if (aString.indexOf('.') != -1) {}     // magic number -1, by default ignored
+    if (aString.indexOf('.') >= 0) { }     // alternative approach
+
+    if (aDouble > 0.0) {}                  // magic number 0.0
+    if (aDouble >= Double.MIN_VALUE) {}    // preferred approach
+
+    // with rule property "ignoreExpressions" set to "false"
+    if (i == pos + 5) {}  // violation: magic number 5 within an (additive) expression
+    if (i == pos + SUFFIX_LENGTH) {} // preferred approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidLosingExceptionInformation"
+          since="4.2.6"
+          language="java"
+          message="Avoid statements in a catch block that invoke accessors on the exception without using the information"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidlosingexceptioninformation">
+        <description>
+            Statements in a catch block that invoke accessors on the exception without using the information
+            only add to code size.  Either remove the invocation, or use the return result.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/Block/BlockStatement/Statement/StatementExpression/PrimaryExpression/PrimaryPrefix/Name
+[
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getLocalizedMessage')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getCause')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.getStackTrace')
+   or
+   @Image = concat(../../../../../../../FormalParameter/VariableDeclaratorId/@Name, '.toString')
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    try {
+        // do something
+    } catch (SomeException se) {
+        se.getMessage();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidMultipleUnaryOperators"
+          language="java"
+          since="4.2"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidMultipleUnaryOperatorsRule"
+          message="Using multiple unary operators may be a bug, and/or is confusing."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidmultipleunaryoperators">
+        <description>
+            The use of multiple unary operators may be problematic, and/or confusing.
+            Ensure that the intended usage is not a bug, or consider simplifying the expression.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+// These are typo bugs, or at best needlessly complex and confusing:
+int i = - -1;
+int j = + - +1;
+int z = ~~2;
+boolean b = !!true;
+boolean c = !!!true;
+
+// These are better:
+int i = 1;
+int j = -1;
+int z = 2;
+boolean b = true;
+boolean c = false;
+
+// And these just make your brain hurt:
+int i = ~-2;
+int j = -~7;
+]]>
+        </example>
+    </rule>
+
+    <rule name="AvoidUsingOctalValues"
+          language="java"
+          since="3.9"
+          message="Do not start a literal by 0 unless it's an octal value"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.AvoidUsingOctalValuesRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#avoidusingoctalvalues">
+        <description>
+            Integer literals should not start with zero since this denotes that the rest of literal will be
+            interpreted as an octal value.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+int i = 012;    // set i with 10 not 12
+int j = 010;    // set j with 8 not 10
+k = i * j;      // set k with 80 not 120
+]]>
+        </example>
+    </rule>
+
+    <rule name="BadComparison" ref="ComparisonWithNaN" deprecated="true" />
+
+    <rule name="BeanMembersShouldSerialize"
+          language="java"
+          since="1.1"
+          message="Found non-transient, non-static member. Please mark as transient or provide accessors."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BeanMembersShouldSerializeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#beanmembersshouldserialize">
+        <description>
+            If a class is a bean, or is referenced by a bean directly or indirectly it needs to be serializable.
+            Member variables need to be marked as transient, static, or have accessor methods in the class. Marking
+            variables as transient is the safest and easiest modification. Accessor methods should follow the Java
+            naming conventions, i.e. for a variable named foo, getFoo() and setFoo() accessor methods should be provided.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+private transient int someFoo;  // good, it's transient
+private static int otherFoo;    // also OK
+private int moreFoo;            // OK, has proper accessors, see below
+private int badFoo;             // bad, should be marked transient
+
+private void setMoreFoo(int moreFoo){
+      this.moreFoo = moreFoo;
+}
+
+private int getMoreFoo(){
+      return this.moreFoo;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="BrokenNullCheck"
+          language="java"
+          since="3.8"
+          message="Method call on object which may be null"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.BrokenNullCheckRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#brokennullcheck">
+        <description>
+            The null check is broken since it will throw a NullPointerException itself.
+            It is likely that you used || instead of &amp;&amp; or vice versa.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+public String bar(String string) {
+  // should be &&
+    if (string!=null || !string.equals(""))
+        return string;
+  // should be ||
+    if (string==null && string.equals(""))
+        return string;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperFirst"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the start of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperfirst">
+        <description>Super should be called at the start of the method</description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='onCreate' or
+  @Name='onConfigurationChanged' or
+  @Name='onPostCreate' or
+  @Name='onPostResume' or
+  @Name='onRestart' or
+  @Name='onRestoreInstanceState' or
+  @Name='onResume' or
+  @Name='onStart'
+  ]
+    /Block[not(
+      (BlockStatement[1]/Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name]))]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onCreate(Bundle bundle) {
+        // missing call to super.onCreate(bundle)
+        foo();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CallSuperLast"
+          since="4.2.5"
+          language="java"
+          message="super should be called at the end of the method"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#callsuperlast">
+        <description>
+            Super should be called at the end of the method
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[
+  @Name='finish' or
+  @Name='onDestroy' or
+  @Name='onPause' or
+  @Name='onSaveInstanceState' or
+  @Name='onStop' or
+  @Name='onTerminate'
+  ]
+   /Block/BlockStatement[last()]
+    [not(Statement/StatementExpression/PrimaryExpression[./PrimaryPrefix[@SuperModifier= true()]]/PrimarySuffix[@Image= ancestor::MethodDeclaration/@Name])]
+[ancestor::ClassOrInterfaceDeclaration[ExtendsList/ClassOrInterfaceType[
+  pmd-java:typeIs('android.app.Activity') or
+  pmd-java:typeIs('android.app.Application') or
+  pmd-java:typeIs('android.app.Service')
+]]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class DummyActivity extends Activity {
+    public void onPause() {
+        foo();
+        // missing call to super.onPause()
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CheckSkipResult"
+          language="java"
+          since="5.0"
+          message="Check the value returned by the skip() method of an InputStream to see if the requested number of bytes has been skipped."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CheckSkipResultRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#checkskipresult">
+        <description>
+            The skip() method may skip a smaller number of bytes than requested. Check the returned value to find out if it was the case or not.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private FileInputStream _s = new FileInputStream("file");
+
+   public void skip(int n) throws IOException {
+      _s.skip(n); // You are not sure that exactly n bytes are skipped
+   }
+
+   public void skipExactly(int n) throws IOException {
+      while (n != 0) {
+         long skipped = _s.skip(n);
+         if (skipped == 0)
+            throw new EOFException();
+         n -= skipped;
+      }
+   }
+]]>
+        </example>
+    </rule>
+
+    <rule name="ClassCastExceptionWithToArray"
+          language="java"
+          since="3.4"
+          message="This usage of the Collection.toArray() method will throw a ClassCastException."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#classcastexceptionwithtoarray">
+        <description>
+            When deriving an array of a specific class from your Collection, one should provide an array of
+            the same class as the parameter of the toArray() method. Doing otherwise you will will result
+            in a ClassCastException.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CastExpression[Type/ReferenceType/ClassOrInterfaceType[@Image != "Object"]]
+    /PrimaryExpression
+    [PrimaryPrefix/Name[ends-with(@Image, '.toArray')]]
+    [PrimarySuffix/Arguments[not(*)]]
+    [count(PrimarySuffix) = 1]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+Collection c = new ArrayList();
+Integer obj = new Integer(1);
+c.add(obj);
+
+    // this would trigger the rule (and throw a ClassCastException if executed)
+Integer[] a = (Integer [])c.toArray();
+
+   // this is fine and will not trigger the rule
+Integer[] b = (Integer [])c.toArray(new Integer[c.size()]);
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustBePublic"
+          language="java"
+          since="5.4.0"
+          message="clone() method must be public if the class implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustbepublic">
+        <description>
+            The java Manual says "By convention, classes that implement this interface should override
+            Object.clone (which is protected) with a public method."
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Public= false()]
+  [@Name = 'clone']
+  [@Arity = 0]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() throws CloneNotSupportedException { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    protected Foo clone() { // Violation, must be public
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Object clone() // Ok
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodMustImplementCloneable"
+          language="java"
+          since="1.9"
+          message="clone() method should be implemented only if implementing Cloneable interface"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloneMethodMustImplementCloneableRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodmustimplementcloneable">
+        <description>
+            The method clone() should only be implemented if the class implements the Cloneable interface with the exception of
+            a final method that only throws CloneNotSupportedException.
+
+            The rule can also detect, if the class implements or extends a Cloneable class.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class MyClass {
+ public Object clone() throws CloneNotSupportedException {
+  return foo;
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneMethodReturnTypeMustMatchClassName"
+          language="java"
+          minimumLanguageVersion="1.5"
+          since="5.4.0"
+          message="The return type of the clone() method must be the class name when implements Cloneable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonemethodreturntypemustmatchclassname">
+        <description>
+            If a class implements cloneable the return type of the method clone() must be the class name. That way, the caller
+            of the clone method doesn't need to cast the returned clone to the correct type.
+
+            Note: This is only possible with Java 1.5 or higher.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and not (ResultType//ClassOrInterfaceType/@Image = ancestor::ClassOrInterfaceDeclaration[1]/@SimpleName)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements Cloneable {
+    @Override
+    protected Object clone() { // Violation, Object must be Foo
+    }
+}
+
+public class Foo implements Cloneable {
+    @Override
+    public Foo clone() { //Ok
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloneThrowsCloneNotSupportedException"
+          deprecated="true"
+          language="java"
+          since="1.9"
+          message="clone() method should throw CloneNotSupportedException"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#clonethrowsclonenotsupportedexception">
+        <description>
+            The method clone() should throw a CloneNotSupportedException.
+
+            This rule is deprecated since PMD 6.35.0 without replacement. The rule has no real value as
+            `CloneNotSupportedException` is a checked exception and therefore you need to deal with it while
+            implementing the `clone()` method. You either need to declare the exception or catch it. If you catch it,
+            then subclasses can't throw it themselves explicitly. However, `Object.clone()` will still throw this
+            exception if the `Cloneable` interface is not implemented.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+@Name = 'clone'
+and @Arity = 0
+and count(NameList/Name[contains
+(@Image,'CloneNotSupportedException')]) = 0
+]
+[
+../../../../ClassOrInterfaceDeclaration[@Final = false()]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyClass implements Cloneable{
+    public Object clone() { // will cause an error
+         MyClass clone = (MyClass)super.clone();
+         return clone;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CloseResource"
+          language="java"
+          since="1.2.2"
+          message="Ensure that resources like this {0} object are closed after use"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.CloseResourceRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#closeresource">
+        <description>
+            Ensure that resources (like `java.sql.Connection`, `java.sql.Statement`, and `java.sql.ResultSet` objects
+            and any subtype of `java.lang.AutoCloseable`) are always closed after use.
+            Failing to do so might result in resource leaks.
+
+            Note: It suffices to configure the super type, e.g. `java.lang.AutoClosable`, so that this rule automatically triggers
+            on any subtype (e.g. `java.io.FileInputStream`). Additionally specifying `java.sql.Connection` helps in detecting
+            the types, if the type resolution / auxclasspath is not correctly setup.
+
+            Note: Since PMD 6.16.0 the default value for the property `types` contains `java.lang.AutoCloseable` and detects
+            now cases where the standard `java.io.*Stream` classes are involved. In order to restore the old behaviour,
+            just remove "AutoCloseable" from the types.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Bar {
+    public void withSQL() {
+        Connection c = pool.getConnection();
+        try {
+            // do stuff
+        } catch (SQLException ex) {
+           // handle exception
+        } finally {
+            // oops, should close the connection using 'close'!
+            // c.close();
+        }
+    }
+
+    public void withFile() {
+        InputStream file = new FileInputStream(new File("/tmp/foo"));
+        try {
+            int c = file.in();
+        } catch (IOException e) {
+            // handle exception
+        } finally {
+            // TODO: close file
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="CompareObjectsWithEquals"
+          language="java"
+          since="3.2"
+          message="Use equals() to compare object references."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#compareobjectswithequals">
+        <description>
+            Use `equals()` to compare object references; avoid comparing them with `==`.
+
+            Since comparing objects with named constants is useful in some cases (eg, when
+            defining constants for sentinel values), the rule ignores comparisons against
+            fields with all-caps name (eg `this == SENTINEL`), which is a common naming
+            convention for constant fields.
+
+            You may allow some types to be compared by reference by listing the exceptions
+            in the `typesThatCompareByReference` property.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="typesThatCompareByReference" type="List[String]" delimiter="," description="List of canonical type names for which reference comparison is allowed.">
+                <value>java.lang.Enum,java.lang.Class</value>
+            </property>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EqualityExpression
+    [count(
+        PrimaryExpression[pmd-java:typeIs('java.lang.Object')]
+        [not(some $t in $typesThatCompareByReference satisfies pmd-java:typeIs($t))]
+       ) = 2
+    ]
+    [not(PrimaryExpression[PrimaryPrefix/@ThisModifier = true()]
+                          [not(PrimarySuffix)]
+                          [ancestor::MethodDeclaration[@Name = 'equals']])
+    ]
+    (: Is not a field access with an all-caps identifier :)
+    [not(PrimaryExpression[not(PrimarySuffix) and PrimaryPrefix/Name[upper-case(@Image)=@Image]
+     or PrimaryExpression/PrimarySuffix[last()][upper-case(@Image)=@Image]])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+class Foo {
+  boolean bar(String a, String b) {
+    return a == b;
+  }
+}
+
+]]>
+        </example>
+    </rule>
+
+    <rule name="ComparisonWithNaN"
+          language="java"
+          since="6.36.0"
+          message="Comparisons with NaN always return false"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+        <description><![CDATA[
+            Reports comparisons with double and float `NaN` (Not-a-Number) values.
+            These are [specified](https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.21.1)
+            to have unintuitive behavior: NaN is considered unequal to itself.
+            This means a check like `someDouble == Double.NaN` will always return
+            false, even if `someDouble` is really the NaN value. To test whether a
+            value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+            (or `Float.isNaN`). The `!=` operator should be treated similarly.
+            Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+            and will always evaluate to false.
+
+            This rule has been renamed from "BadComparison" with PMD 6.36.0.
+        ]]></description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+        </example>
+    </rule>
+
+
+    <rule name="ConstructorCallsOverridableMethod"
+          language="java"
+          since="1.04"
+          message="Overridable {0} called during object construction"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#constructorcallsoverridablemethod">
+        <description>
+            Calling overridable methods during construction poses a risk of invoking methods on an incompletely
+            constructed object and can be difficult to debug.
+            It may leave the sub-class unable to construct its superclass or forced to replicate the construction
+            process completely within itself, losing the ability to call super().  If the default constructor
+            contains a call to an overridable method, the subclass may be completely uninstantiable.   Note that
+            this includes method calls throughout the control flow graph - i.e., if a constructor Foo() calls a
+            private method bar() that calls a public method buz(), this denotes a problem.
+        </description>
+        <priority>1</priority>
+        <example>
+            <![CDATA[
+public class SeniorClass {
+  public SeniorClass(){
+      toString(); //may throw NullPointerException if overridden
+  }
+  public String toString(){
+    return "IAmSeniorClass";
+  }
+}
+public class JuniorClass extends SeniorClass {
+  private String name;
+  public JuniorClass(){
+    super(); //Automatic call leads to NullPointerException
+    name = "JuniorClass";
+  }
+  public String toString(){
+    return name.toUpperCase();
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DataflowAnomalyAnalysis"
+          language="java"
+          since="3.9"
+          message="Found ''{0}''-anomaly for variable ''{1}'' (lines ''{2}''-''{3}'')."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DataflowAnomalyAnalysisRule"
+          dfa="true"
+          deprecated="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dataflowanomalyanalysis">
+        <description>The dataflow analysis tracks local definitions, undefinitions and references to variables on different paths on the data flow.
+            From those informations there can be found various problems.
+
+            1. DU - Anomaly: A recently defined variable is undefined. These anomalies may appear in normal source text.
+            2. DD - Anomaly: A recently defined variable is redefined. This is ominous but don't have to be a bug.
+
+            This rule is deprecated. Use {% rule "java/bestpractices/UnusedAssignment" %} in category bestpractices instead.
+        </description>
+        <priority>5</priority>
+        <example>
+            <![CDATA[
+public void foo() {
+  int buz = 5;
+  buz = 6; // redefinition of buz -> dd-anomaly
+  foo(buz);
+  buz = 2;
+} // buz is undefined when leaving scope -> du-anomaly
+]]>
+        </example>
+    </rule>
+
+    <rule name="DetachedTestCase"
+          language="java"
+          since="6.13.0"
+          message="Probable detached JUnit test case."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#detachedtestcase">
+        <description>
+            The method appears to be a test case since it has public or default visibility,
+            non-static access, no arguments, no return value, has no annotations, but is a
+            member of a class that has one or more JUnit test cases. If it is a utility
+            method, it should likely have private visibility. If it is an ignored test, it
+            should be annotated with @Test and @Ignore.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value><![CDATA[
+//ClassOrInterfaceBodyDeclaration
+[../ClassOrInterfaceBodyDeclaration/Annotation/*/Name
+        [pmd-java:typeIs('org.junit.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.Test')
+         or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestFactory')
+         or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
+         or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')]
+]
+[not(Annotation)]
+[MethodDeclaration[(@Public = true() or @PackagePrivate = true()) and @Static = false() and
+        ResultType[@Void = true()] and
+        MethodDeclarator/FormalParameters[@Size = 0]
+    ]
+]
+]]></value>
+            </property>
+            <property name="version" value="2.0" />
+        </properties>
+        <example>
+            <![CDATA[
+public class MyTest {
+    @Test
+    public void someTest() {
+    }
+
+    // violation: Not annotated
+    public void someOtherTest () {
+    }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallGarbageCollectionExplicitly"
+          language="java"
+          since="4.2"
+          message="Do not explicitly trigger a garbage collection."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotcallgarbagecollectionexplicitly">
+        <description>
+            Calls to System.gc(), Runtime.getRuntime().gc(), and System.runFinalization() are not advised. Code should have the
+            same behavior whether the garbage collection is disabled using the option -Xdisableexplicitgc or not.
+            Moreover, "modern" jvms do a very good job handling garbage collections. If memory usage issues unrelated to memory
+            leaks develop within an application, it should be dealt with JVM options rather than within the code itself.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+(starts-with(@Image, 'System.') and
+(starts-with(@Image, 'System.gc') or
+starts-with(@Image, 'System.runFinalization'))) or
+(
+starts-with(@Image,'Runtime.getRuntime') and
+../../PrimarySuffix[ends-with(@Image,'gc')]
+)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class GCCall {
+    public GCCall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+
+    public explicitGCcall() {
+        // Explicit gc call !
+        System.gc();
+    }
+
+    public void doSomething() {
+        // Explicit gc call !
+        Runtime.getRuntime().gc();
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotCallSystemExit" ref="category/java/errorprone.xml/DoNotTerminateVM" deprecated="true" />
+
+    <rule name="DoNotExtendJavaLangThrowable"
+          language="java"
+          since="6.0.0"
+          message="Exceptions should not extend java.lang.Throwable"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotextendjavalangthrowable">
+        <description>
+            Extend Exception or RuntimeException instead of Throwable.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration/ExtendsList/ClassOrInterfaceType
+  [@Image="Throwable" or @Image="java.lang.Throwable"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo extends Throwable { }
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotHardCodeSDCard"
+          since="4.2.6"
+          language="java"
+          message="Do not hardcode /sdcard."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donothardcodesdcard">
+        <description>
+            Use Environment.getExternalStorageDirectory() instead of "/sdcard"
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Literal[starts-with(@Image,'"/sdcard')]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyActivity extends Activity {
+    protected void foo() {
+        String storageLocation = "/sdcard/mypackage";   // hard-coded, poor approach
+
+       storageLocation = Environment.getExternalStorageDirectory() + "/mypackage"; // preferred approach
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotTerminateVM"
+          language="java"
+          since="4.1"
+          message="System.exit() should not be used in J2EE/JEE apps"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotterminatevm">
+        <description>
+            Web applications should not call `System.exit()`, since only the web container or the
+            application server should stop the JVM. Otherwise a web application would terminate all other applications
+            running on the same application server.
+
+            This rule also checks for the equivalent calls `Runtime.getRuntime().exit()` and `Runtime.getRuntime().halt()`.
+
+            This rule was called *DoNotCallSystemExit* until PMD 6.29.0.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Name[
+    starts-with(@Image,'System.exit')
+    or
+    (starts-with(@Image,'Runtime.getRuntime') and ../../PrimarySuffix[ends-with(@Image,'exit') or ends-with(@Image,'halt')])
+][not(ancestor::MethodDeclaration[1][@Name="main" and @Static = true()])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    System.exit(0);                 // never call this when running in an application server!
+}
+public void foo() {
+    Runtime.getRuntime().exit(0);   // never stop the JVM manually, the container will do this.
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DoNotThrowExceptionInFinally"
+          language="java"
+          since="4.2"
+          message="A throw statement in a finally block makes the control flow hard to understand."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#donotthrowexceptioninfinally">
+        <description>
+            Throwing exceptions within a 'finally' block is confusing since they may mask other exceptions
+            or code defects.
+            Note: This is a PMD implementation of the Lint4j rule "A throw in a finally block"
+        </description>
+        <priority>4</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//FinallyStatement[descendant::ThrowStatement]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            // Here do some stuff
+        } catch( Exception e) {
+            // Handling the issue
+        } finally {
+            // is this really a good idea ?
+            throw new Exception();
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontImportSun"
+          language="java"
+          since="1.5"
+          message="Avoid importing anything from the 'sun.*' packages"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.DontImportSunRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontimportsun">
+        <description>
+            Avoid importing anything from the 'sun.*' packages.  These packages are not portable and are likely to change.
+        </description>
+        <priority>4</priority>
+        <example>
+            <![CDATA[
+import sun.misc.foo;
+public class Foo {}
+]]>
+        </example>
+    </rule>
+
+    <rule name="DontUseFloatTypeForLoopIndices"
+          language="java"
+          since="4.3"
+          message="Don't use floating point for loop indices. If you must use floating point, use double."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#dontusefloattypeforloopindices">
+        <description>
+            Don't use floating point for loop indices. If you must use floating point, use double
+            unless you're certain that float provides enough precision and you have a compelling
+            performance need (space or time).
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ForStatement/ForInit/LocalVariableDeclaration
+/Type/PrimitiveType[@Image="float"]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Count {
+  public static void main(String[] args) {
+    final int START = 2000000000;
+    int count = 0;
+    for (float f = START; f < START + 50; f++)
+      count++;
+      //Prints 0 because (float) START == (float) (START + 50).
+      System.out.println(count);
+      //The termination test misbehaves due to floating point granularity.
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyCatchBlock"
+          language="java"
+          since="0.1"
+          message="Avoid empty catch blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptycatchblock">
+        <description>
+            Empty Catch Block finds instances where an exception is caught, but nothing is done.
+            In most circumstances, this swallows an exception which should either be acted on
+            or reported.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement
+ [not(Block/BlockStatement)]
+ [$allowCommentedBlocks != true() or Block/@containsComment = false()]
+ [FormalParameter/Type/ReferenceType
+   /ClassOrInterfaceType[@Image != 'InterruptedException' and @Image != 'CloneNotSupportedException']
+ ]
+ [FormalParameter/VariableDeclaratorId[not(matches(@Name, $allowExceptionNameRegex))]]
+]]>
+                </value>
+            </property>
+            <property name="allowCommentedBlocks" type="Boolean" description="Empty blocks containing comments will be skipped" value="false"/>
+            <property name="allowExceptionNameRegex" type="String" description="Empty blocks catching exceptions with names matching this regular expression will be skipped" value="^(ignored|expected)$"/>
+        </properties>
+        <example>
+            <![CDATA[
+public void doSomething() {
+    try {
+        FileInputStream fis = new FileInputStream("/tmp/bugger");
+    } catch (IOException ioe) {
+        // not good
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinalizer"
+          language="java"
+          since="1.5"
+          message="Avoid empty finalize methods"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinalizer">
+        <description>
+            Empty finalize methods serve no purpose and should be removed. Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Name='finalize'][@Arity = 0]
+  /Block[not(*)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+   protected void finalize() {}
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyFinallyBlock"
+          language="java"
+          since="0.4"
+          message="Avoid empty finally blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyfinallyblock">
+        <description>
+            Empty finally blocks serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//FinallyStatement[not(Block/BlockStatement)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+            int x=2;
+        } finally {
+            // empty!
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyIfStmt"
+          language="java"
+          since="0.1"
+          message="Avoid empty 'if' statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyifstmt">
+        <description>
+            Empty If Statement finds instances where a condition is checked but nothing is done about it.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//IfStatement/Statement
+ [EmptyStatement or Block[not(*)]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+ void bar(int x) {
+  if (x == 0) {
+   // empty!
+  }
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyInitializer"
+          language="java"
+          since="5.0"
+          message="Empty initializer was found"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyinitializer">
+        <description>
+            Empty initializers serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//Initializer/Block[not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   static {} // Why ?
+
+   {} // Again, why ?
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyStatementBlock"
+          language="java"
+          since="5.0"
+          message="Avoid empty block statements."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptystatementblock">
+        <description>
+            Empty block statements serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//BlockStatement/Statement/Block[not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+   private int _bar;
+
+   public void setBar(int bar) {
+      { _bar = bar; } // Why not?
+      {} // But remove this.
+   }
+
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyStatementNotInLoop"
+          language="java"
+          since="1.5"
+          message="An empty statement (semicolon) not part of a loop"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptystatementnotinloop">
+        <description>
+            An empty statement (or a semicolon by itself) that is not used as the sole body of a 'for'
+            or 'while' loop is probably a bug.  It could also be a double semicolon, which has no purpose
+            and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EmptyStatement
+ [not(
+       ../../../ForStatement
+       or ../../../WhileStatement
+       or ../../../BlockStatement/ClassOrInterfaceDeclaration
+       or ../../../../../../ForStatement/Statement[1]
+        /Block[1]/BlockStatement[1]/Statement/EmptyStatement
+       or ../../../../../../WhileStatement/Statement[1]
+        /Block[1]/BlockStatement[1]/Statement/EmptyStatement)
+ ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void doit() {
+      // this is probably not what you meant to do
+      ;
+      // the extra semicolon here this is not necessary
+      System.out.println("look at the extra semicolon");;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptySwitchStatements"
+          language="java"
+          since="1.0"
+          message="Avoid empty switch statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptyswitchstatements">
+        <description>
+            Empty switch statements serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//SwitchStatement[count(*) = 1]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar() {
+    int x = 2;
+    switch (x) {
+        // once there was code here
+        // but it's been commented out or something
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptySynchronizedBlock"
+          language="java"
+          since="1.3"
+          message="Avoid empty synchronized blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptysynchronizedblock">
+        <description>
+            Empty synchronized blocks serve no purpose and should be removed.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//SynchronizedStatement/Block[1][not(*)]</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        synchronized (this) {
+            // empty!
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyTryBlock"
+          language="java"
+          since="0.4"
+          message="Avoid empty try blocks"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptytryblock">
+        <description>
+            Avoid empty try blocks - what's the point?
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//TryStatement[not(ResourceSpecification)]/Block[1][not(*)]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void bar() {
+        try {
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="EmptyWhileStmt"
+          language="java"
+          since="0.2"
+          message="Avoid empty 'while' statements"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#emptywhilestmt">
+        <description>
+            Empty While Statement finds all instances where a while statement does nothing.
+            If it is a timing loop, then you should use Thread.sleep() for it; if it is
+            a while loop that does a lot in the exit expression, rewrite it to make it clearer.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//WhileStatement/Statement[Block[not(*)] or EmptyStatement]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+void bar(int a, int b) {
+    while (a == b) {
+        // empty!
+    }
+}
+ ]]>
+        </example>
+    </rule>
+
+    <rule name="EqualsNull"
+          language="java"
+          since="1.9"
+          message="Avoid using equals() to compare against null"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#equalsnull">
+        <description>
+            Tests for null should not use the equals() method. The '==' operator should be used instead.
+        </description>
+        <priority>1</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimaryExpression
+  [
+    PrimaryPrefix[Name[ends-with(@Image, 'equals')]]
+      [following-sibling::node()/Arguments/ArgumentList[count(Expression)=1]
+          /Expression/PrimaryExpression/PrimaryPrefix/Literal/NullLiteral]
+
+    or
+
+    PrimarySuffix[ends-with(@Image, 'equals')]
+      [following-sibling::node()/Arguments/ArgumentList[count(Expression)=1]
+          /Expression/PrimaryExpression/PrimaryPrefix/Literal/NullLiteral]
+
+  ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+String x = "foo";
+
+if (x.equals(null)) {   // bad form
+    doSomething();
+}
+
+if (x == null) {        // preferred
+    doSomething();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="FinalizeDoesNotCallSuperFinalize"
+          language="java"
+          since="1.5"
+          message="Last statement in finalize method should be a call to super.finalize()"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#finalizedoesnotcallsuperfinalize">
+        <description>
+            If the finalize() is implemented, its last action should be to call super.finalize. Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <!-- in English: a method declaration of finalize(), with no arguments, containing
+                    a block whose last statement is NOT a call to super.finalize -->
+                    <![CDATA[
+//MethodDeclaration[@Name='finalize'][@Arity = 0]
+   /Block
+      /BlockStatement[last()]
+      [not(Statement/StatementExpression/PrimaryExpression
+            [./PrimaryPrefix[@SuperModifier= true()]]
+            [./PrimarySuffix[@Image='finalize']]
+          )
+      ]
+      [not(Statement/TryStatement/FinallyStatement
+       /Block/BlockStatement/Statement/StatementExpression/PrimaryExpression
+            [./PrimaryPrefix[@SuperModifier= true()]]
+            [./PrimarySuffix[@Image='finalize']]
+          )
+      ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+protected void finalize() {
+    something();
+    // neglected to call super.finalize()
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="FinalizeOnlyCallsSuperFinalize"
+          language="java"
+          since="1.5"
+          message="Finalize should do something besides just calling super.finalize()"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#finalizeonlycallssuperfinalize">
+        <description>
+            If the finalize() is implemented, it should do something besides just calling super.finalize(). Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Name='finalize'][@Arity = 0]
+   /Block[count(BlockStatement)=1]
+     /BlockStatement[
+       Statement/StatementExpression/PrimaryExpression
+       [./PrimaryPrefix[@SuperModifier= true()]]
+       [./PrimarySuffix[@Image='finalize']]
+     ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+protected void finalize() {
+    super.finalize();
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="FinalizeOverloaded"
+          language="java"
+          since="1.5"
+          message="Finalize methods should not be overloaded"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#finalizeoverloaded">
+        <description>
+            Methods named finalize() should not have parameters.  It is confusing and most likely an attempt to
+            overload Object.finalize(). It will not be called by the VM.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Name='finalize'][@Arity > 0]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    // this is confusing and probably a bug
+    protected void finalize(int a) {
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="FinalizeShouldBeProtected"
+          language="java"
+          since="1.1"
+          message="If you override finalize(), make it protected"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#finalizeshouldbeprotected">
+        <description>
+            When overriding the finalize(), the new method should be set as protected.  If made public,
+            other classes may invoke it at inappropriate times.
+
+            Note that Oracle has declared Object.finalize() as deprecated since JDK 9.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Protected=false()][@Name='finalize'][@Arity = 0]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void finalize() {
+    // do something
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="IdempotentOperations"
+          language="java"
+          since="2.0"
+          message="Avoid idempotent operations (like assigning a variable to itself)."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.IdempotentOperationsRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#idempotentoperations">
+        <description>
+            Avoid idempotent operations - they have no effect.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+ public void bar() {
+  int x = 2;
+  x = x;
+ }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="ImplicitSwitchFallThrough"
+          language="java"
+          since="3.0"
+          message="A switch statement does not contain a break"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#implicitswitchfallthrough">
+        <description>
+            Switch statements without break or return statements for each case option
+            may indicate problematic behaviour. Empty cases are ignored as these indicate an intentional fall-through.
+
+            This rule has been renamed from "MissingBreakInSwitch" with PMD 6.37.0.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//SwitchStatement
+[(count(.//BreakStatement)
+ + count(BlockStatement//Statement/ReturnStatement)
+ + count(BlockStatement//Statement/ContinueStatement)
+ + count(BlockStatement//Statement/ThrowStatement)
+ + count(BlockStatement//Statement/IfStatement[@Else= true() and Statement[2][ReturnStatement|ContinueStatement|ThrowStatement]]/Statement[1][ReturnStatement|ContinueStatement|ThrowStatement])
+ + count(SwitchLabel[ following-sibling::node()[1][self::SwitchLabel] ])
+ + count(SwitchLabel[count(following-sibling::node()) = 0])
+  < count (SwitchLabel))]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public void bar(int status) {
+    switch(status) {
+      case CANCELLED:
+        doCancelled();
+        // break; hm, should this be commented out?
+      case NEW:
+        doNew();
+        // is this really a fall-through?
+      case REMOVED:
+        doRemoved();
+        // what happens if you add another case after this one?
+      case OTHER: // empty case - this is interpreted as an intentional fall-through
+      case ERROR:
+        doErrorHandling();
+        break;
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="ImportFromSamePackage"
+          language="java"
+          since="1.02"
+          deprecated="true"
+          message="No need to import a type that lives in the same package"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.ImportFromSamePackageRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#importfromsamepackage">
+        <description>
+            There is no need to import a type that lives in the same package.
+
+            This rule is deprecated since PMD 6.34.0. Use the rule {% rule "java/codestyle/UnnecessaryImport" %}
+            from category codestyle instead.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+package foo;
+
+import foo.Buz;     // no need for this
+import foo.*;       // or this
+
+public class Bar{}
+]]>
+        </example>
+    </rule>
+
+    <rule name="InstantiationToGetClass"
+          language="java"
+          since="2.0"
+          message="Avoid instantiating an object just to call getClass() on it; use the .class public member instead"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#instantiationtogetclass">
+        <description>
+            Avoid instantiating an object just to call getClass() on it; use the .class public member instead.
+        </description>
+        <priority>4</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//PrimarySuffix
+ [@Image='getClass']
+ [parent::PrimaryExpression
+  [PrimaryPrefix/AllocationExpression]
+  [count(PrimarySuffix) = 2]
+ ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+// replace this
+Class c = new String().getClass();
+
+// with this:
+Class c = String.class;
+]]>
+        </example>
+    </rule>
+
+    <rule name="InvalidSlf4jMessageFormat"
+          ref="category/java/errorprone.xml/InvalidLogMessageFormat"
+          deprecated="true" />
+
+    <rule name="InvalidLogMessageFormat"
+          language="java"
+          since="5.5.0"
+          message="Invalid message format"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.InvalidLogMessageFormatRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#invalidlogmessageformat">
+        <description>
+            Check for messages in slf4j and log4j2 (since 6.19.0) loggers with non matching number of arguments and placeholders.
+
+            Since 6.32.0 in addition to parameterized message placeholders (`{}`) also format specifiers of string formatted
+            messages are supported (`%s`).
+        </description>
+        <priority>5</priority>
+        <example>
+            <![CDATA[
+LOGGER.error("forget the arg {}");
+LOGGER.error("forget the arg %s");
+LOGGER.error("too many args {}", "arg1", "arg2");
+LOGGER.error("param {}", "arg1", new IllegalStateException("arg")); //The exception is shown separately, so is correct.
+]]>
+        </example>
+    </rule>
+
+    <rule name="JumbledIncrementer"
+          language="java"
+          since="1.0"
+          message="Avoid modifying an outer loop incrementer in an inner loop for update expression"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#jumbledincrementer">
+        <description>
+            Avoid jumbled loop incrementers - its usually a mistake, and is confusing even if intentional.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value><![CDATA[
+//ForStatement
+  [
+    ForUpdate/StatementExpressionList/StatementExpression/PostfixExpression/PrimaryExpression/PrimaryPrefix/Name/@Image
+    =
+    ancestor::ForStatement/ForInit//VariableDeclaratorId/@Name
+  ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class JumbledIncrementerRule1 {
+    public void foo() {
+        for (int i = 0; i < 10; i++) {          // only references 'i'
+            for (int k = 0; k < 20; i++) {      // references both 'i' and 'k'
+                System.out.println("Hello");
+            }
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="JUnitSpelling"
+          language="java"
+          since="1.0"
+          message="You may have misspelled a JUnit framework method (setUp or tearDown)"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.JUnitSpellingRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#junitspelling">
+        <description>
+            In JUnit 3, the setUp method is used to set up all data entities required in running tests.
+            The tearDown method is used to clean up all data entities required in running tests.
+            You should not misspell method name if you want your test to set up and clean up everything correctly.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+import junit.framework.*;
+
+public class Foo extends TestCase {
+    public void setup() {}    // oops, should be setUp
+    public void TearDown() {} // oops, should be tearDown
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="JUnitStaticSuite"
+          language="java"
+          since="1.0"
+          message="You have a suite() method that is not both public and static, so JUnit won't call it to get your TestSuite.  Is that what you wanted to do?"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.JUnitStaticSuiteRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#junitstaticsuite">
+        <description>
+            The suite() method in a JUnit test needs to be both public and static.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+import junit.framework.*;
+
+public class Foo extends TestCase {
+    public void suite() {}         // oops, should be static
+    private static void suite() {} // oops, should be public
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="LoggerIsNotStaticFinal"
+          language="java"
+          since="2.0"
+          message="The Logger variable declaration does not contain the static and final modifiers"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#loggerisnotstaticfinal"
+          deprecated="true">
+        <description>
+            In most cases, the Logger reference can be declared as static and final.
+
+            This rule is deprecated and will be removed with PMD 7.0.0.
+            The rule is replaced by {% rule java/errorprone/ProperLogger %}.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//VariableDeclarator
+ [parent::FieldDeclaration]
+ [../Type/ReferenceType
+  /ClassOrInterfaceType[@Image='Logger']
+   and
+  (..[@Final= false()] or ..[@Static = false()] ) ]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo{
+    Logger log = Logger.getLogger(Foo.class.getName());                 // not recommended
+
+    static final Logger log = Logger.getLogger(Foo.class.getName());    // preferred approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="MethodWithSameNameAsEnclosingClass"
+          language="java"
+          since="1.5"
+          message="Classes should not have non-constructor methods with the same name as the class"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.MethodWithSameNameAsEnclosingClassRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#methodwithsamenameasenclosingclass">
+        <description>
+            Non-constructor methods should not have the same name as the enclosing class.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class MyClass {
+
+    public MyClass() {}         // this is OK because it is a constructor
+
+    public void MyClass() {}    // this is bad because it is a method
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="MisplacedNullCheck"
+          language="java"
+          since="3.5"
+          message="The null check here is misplaced; if the variable ''{0}'' is null there will be a NullPointerException"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#misplacednullcheck">
+        <description>
+            The null check here is misplaced. If the variable is null a NullPointerException will be thrown.
+            Either the check is useless (the variable will never be "null") or it is incorrect.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ConditionalAndExpression
+  /EqualityExpression
+    [@Image = '!=']
+    (: one side is null :)
+    [PrimaryExpression/PrimaryPrefix/Literal/NullLiteral]
+    (: other side checks for the variable used somewhere in the first child of conditional and expression :)
+    [some $var in preceding-sibling::PrimaryExpression//Name
+      [not(ancestor::ConditionalOrExpression/EqualityExpression[@Image = '=='])]
+      /@Image
+      satisfies starts-with($var, concat(PrimaryExpression/PrimaryPrefix/Name/@Image, '.'))]
+  /PrimaryExpression/PrimaryPrefix/Name
+|
+//ConditionalOrExpression
+  /EqualityExpression
+    [@Image = '==']
+    (: one side is null :)
+    [PrimaryExpression/PrimaryPrefix/Literal/NullLiteral]
+    (: other side checks for the variable used somewhere in the first child of conditional or expression :)
+    [some $var in preceding-sibling::PrimaryExpression//Name
+      [not(ancestor::ConditionalAndExpression/EqualityExpression[@Image = '!='])]
+      /@Image
+      satisfies starts-with($var, concat(PrimaryExpression/PrimaryPrefix/Name/@Image, '.'))]
+  /PrimaryExpression/PrimaryPrefix/Name
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    void bar() {
+        if (a.equals(baz) && a != null) {} // a could be null, misplaced null check
+
+        if (a != null && a.equals(baz)) {} // correct null check
+    }
+}
+]]>
+        </example>
+        <example>
+            <![CDATA[
+public class Foo {
+    void bar() {
+        if (a.equals(baz) || a == null) {} // a could be null, misplaced null check
+
+        if (a == null || a.equals(baz)) {} // correct null check
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="MissingBreakInSwitch" ref="ImplicitSwitchFallThrough" deprecated="true"/>
+
+    <rule name="MissingSerialVersionUID"
+          language="java"
+          since="3.0"
+          message="Classes implementing Serializable should set a serialVersionUID"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#missingserialversionuid">
+        <description>
+            Serializable classes should provide a serialVersionUID field.
+            The serialVersionUID field is also needed for abstract base classes. Each individual class in the inheritance
+            chain needs an own serialVersionUID field. See also [Should an abstract class have a serialVersionUID](https://stackoverflow.com/questions/893259/should-an-abstract-class-have-a-serialversionuid).
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration
+    [@Interface = false()]
+    [count(ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration
+        /FieldDeclaration/VariableDeclarator/VariableDeclaratorId[@Name='serialVersionUID']) = 0]
+    [(ImplementsList | ExtendsList)/ClassOrInterfaceType[pmd-java:typeIs('java.io.Serializable')]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo implements java.io.Serializable {
+    String name;
+    // Define serialization id to avoid serialization related bugs
+    // i.e., public static final long serialVersionUID = 4328743;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="MissingStaticMethodInNonInstantiatableClass"
+          language="java"
+          since="3.0"
+          message="Class cannot be instantiated and does not provide any static methods or fields"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#missingstaticmethodinnoninstantiatableclass">
+        <description>
+            A class that has private constructors and does not have any static methods or fields cannot be used.
+
+            When one of the private constructors is annotated with one of the annotations, then the class is not considered
+            non-instantiatable anymore and no violation will be reported.
+            See the property `annotations`.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="annotations" type="List[String]" delimiter="," value="org.springframework.beans.factory.annotation.Autowired,javax.inject.Inject" description="If a constructor is annotated with one of these annotations, then the class is ignored."/>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration[@Nested= false()]
+[
+  (
+    (: at least one constructor :)
+    ./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/ConstructorDeclaration
+    and
+    (: only private constructors :)count(./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/ConstructorDeclaration) = count(./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/ConstructorDeclaration[@Private= true()])
+    and
+    (: all constructors must not be annotated :)
+    (every $x in $annotations satisfies
+      not(./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/ConstructorDeclaration/
+            ../Annotation/MarkerAnnotation/Name[pmd-java:typeIs($x)]))
+  )
+  and
+  (: no static methods :)not(.//MethodDeclaration[@Static= true()])
+  and
+  (: no (public, package-private, protected) static fields :)not(.//FieldDeclaration[@Private= false()][@Static= true()])
+  and
+  (: no nested classes, that are public and static, and have no constructors at all or a public constructor :)
+  (: and have a method returning the outer class type :)
+  (: or the inner class extends the outer class :)not(.//ClassOrInterfaceDeclaration[@Nested= true()]
+           [@Public= true()]
+           [@Static= true()]
+           [not(./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/ConstructorDeclaration) or ./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/ConstructorDeclaration[@Public= true()]]
+           [(./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/MethodDeclaration
+                [@Public= true()]
+                [./ResultType/Type/ReferenceType/ClassOrInterfaceType
+                    [@Image = //ClassOrInterfaceDeclaration[@Nested= false()]/@SimpleName]
+                ]
+            ) or (
+                ./ExtendsList/ClassOrInterfaceType[@Image = //ClassOrInterfaceDeclaration[@Nested=false()]/@SimpleName]
+            )]
+        )
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+// This class is unusable, since it cannot be
+// instantiated (private constructor),
+// and no static method can be called.
+
+public class Foo {
+  private Foo() {}
+  void foo() {}
+}
+
+]]>
+        </example>
+    </rule>
+
+    <rule name="MoreThanOneLogger"
+          language="java"
+          since="2.0"
+          message="Class contains more than one logger."
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#morethanonelogger">
+        <description>
+            Normally only one logger is used in each class. This rule supports slf4j, log4j, Java Util Logging and
+            log4j2 (since 6.19.0).
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value><![CDATA[
+//ClassOrInterfaceDeclaration[
+  count(
+    ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/FieldDeclaration//ClassOrInterfaceType[
+      pmd-java:typeIs("org.apache.log4j.Logger") or
+      pmd-java:typeIs("org.apache.logging.log4j.Logger") or
+      pmd-java:typeIs("java.util.logging.Logger") or
+      pmd-java:typeIs("org.slf4j.Logger")
+    ]
+  ) > 1
+]
+                ]]></value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    Logger log = Logger.getLogger(Foo.class.getName());
+    // It is very rare to see two loggers on a class, normally
+    // log information is multiplexed by levels
+    Logger log2= Logger.getLogger(Foo.class.getName());
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="NonCaseLabelInSwitchStatement"
+          language="java"
+          since="1.5"
+          message="A non-case label was present in a switch statement"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#noncaselabelinswitchstatement">
+        <description>
+            A non-case label (e.g. a named break/continue label) was present in a switch statement.
+            This legal, but confusing. It is easy to mix up the case labels and the non-case labels.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//SwitchStatement//BlockStatement/Statement/LabeledStatement</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+  void bar(int a) {
+   switch (a) {
+     case 1:
+       // do something
+       break;
+     mylabel: // this is legal, but confusing!
+       break;
+     default:
+       break;
+    }
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="NonStaticInitializer"
+          language="java"
+          since="1.5"
+          message="Non-static initializers are confusing"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#nonstaticinitializer">
+        <description>
+            A non-static initializer block will be called any time a constructor is invoked (just prior to
+            invoking the constructor).  While this is a valid language construct, it is rarely used and is
+            confusing.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0" />
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//Initializer[@Static=false()][not(ancestor::*[3][self::AllocationExpression or self::EnumConstant])]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class MyClass {
+  // this block gets run before any call to a constructor
+  {
+    System.out.println("I am about to construct myself");
+  }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="NullAssignment"
+          language="java"
+          since="1.02"
+          message="Assigning an Object to null is a code smell.  Consider refactoring."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.NullAssignmentRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#nullassignment">
+        <description>
+            Assigning a "null" to a variable (outside of its declaration) is usually bad form.  Sometimes, this type
+            of assignment is an indication that the programmer doesn't completely understand what is going on in the code.
+
+            NOTE: This sort of assignment may used in some cases to dereference objects and encourage garbage collection.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void bar() {
+  Object x = null; // this is OK
+  x = new Object();
+     // big, complex piece of code here
+  x = null; // this is not required
+     // big, complex piece of code here
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="OverrideBothEqualsAndHashcode"
+          language="java"
+          since="0.4"
+          message="Ensure you override both equals() and hashCode()"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.OverrideBothEqualsAndHashcodeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#overridebothequalsandhashcode">
+        <description>
+            Override both public boolean Object.equals(Object other), and public int Object.hashCode(), or override neither.  Even if you are inheriting a hashCode() from a parent class, consider implementing hashCode and explicitly delegating to your superclass.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Bar {        // poor, missing a hashcode() method
+    public boolean equals(Object o) {
+      // do some comparison
+    }
+}
+
+public class Baz {        // poor, missing an equals() method
+    public int hashCode() {
+      // return some hash value
+    }
+}
+
+public class Foo {        // perfect, both methods provided
+    public boolean equals(Object other) {
+      // do some comparison
+    }
+    public int hashCode() {
+      // return some hash value
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="ProperCloneImplementation"
+          language="java"
+          since="1.4"
+          message="Object clone() should be implemented with super.clone()"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.ProperCloneImplementationRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#propercloneimplementation">
+        <description>
+            Object clone() should be implemented with super.clone().
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+class Foo{
+    public Object clone(){
+        return new Foo(); // This is bad
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="ProperLogger"
+          language="java"
+          since="3.3"
+          message="Logger should be defined private static final and have the correct class"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#properlogger"
+          typeResolution="true">
+        <description>
+            A logger should normally be defined private static final and be associated with the correct class.
+            `private final Log log;` is also allowed for rare cases where loggers need to be passed around,
+            with the restriction that the logger needs to be passed into the constructor.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//FieldDeclaration
+[Type/ReferenceType/ClassOrInterfaceType[pmd-java:typeIs($loggerClass)]]
+[
+    (: check modifiers :)
+    (@Private = false() or @Final = false())
+    (: check logger name :)
+    or (@Static and VariableDeclarator/VariableDeclaratorId[@Name != $staticLoggerName])
+    or (@Static = false() and VariableDeclarator/VariableDeclaratorId[@Name != $loggerName])
+
+    (: check logger argument type matches class or enum name :)
+    or .//ArgumentList//ClassOrInterfaceType[@Image != ancestor::ClassOrInterfaceDeclaration/@SimpleName]
+    or .//ArgumentList//ClassOrInterfaceType[@Image != ancestor::EnumDeclaration/@SimpleName]
+]
+[not(
+     (: special case - final logger initialized inside constructor :)
+     not(VariableDeclarator/VariableInitializer)
+     and @Static = false()
+     and
+     ancestor::ClassOrInterfaceBody//ConstructorDeclaration//StatementExpression
+        [PrimaryExpression[PrimaryPrefix[@ThisModifier]]/PrimarySuffix[@Image=$loggerName]]
+        [AssignmentOperator[@Image = '=']]
+        [Expression/PrimaryExpression/PrimaryPrefix/Name[@Image = ancestor::ConstructorDeclaration//FormalParameter/VariableDeclaratorId/@Name]]
+        [not(.//AllocationExpression)]
+  )
+]
+]]>
+                </value>
+            </property>
+            <property name="staticLoggerName" type="String" description="Name of the static Logger variable" value="LOG"/>
+            <property name="loggerName" type="String" description="Name of the Logger instance variable" value="log"/>
+            <property name="loggerClass" type="String" description="Class name of the logger" value="Log"/>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+
+    private static final Log LOG = LogFactory.getLog(Foo.class);    // proper way
+
+    protected Log LOG = LogFactory.getLog(Testclass.class);         // wrong approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="ReturnEmptyArrayRatherThanNull"
+          language="java"
+          since="4.2"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          deprecated="true"
+          message="Return an empty array rather than 'null'."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#returnemptyarrayratherthannull">
+        <description>
+            For any method that returns an array, it is a better to return an empty array rather than a
+            null reference. This removes the need for null checking all results and avoids inadvertent
+            NullPointerExceptions.
+
+            Deprecated since PMD 6.37.0, use {% rule java/errorprone/ReturnEmptyCollectionRatherThanNull %} instead.
+        </description>
+        <priority>1</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+(./ResultType/Type[@ArrayType= true()])
+and
+(./Block/BlockStatement/Statement/ReturnStatement/Expression/PrimaryExpression/PrimaryPrefix/Literal/NullLiteral)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Example {
+    // Not a good idea...
+    public int[] badBehavior() {
+        // ...
+        return null;
+    }
+
+    // Good behavior
+    public String[] bonnePratique() {
+        //...
+        return new String[0];
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="ReturnEmptyCollectionRatherThanNull"
+          language="java"
+          since="6.37.0"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          message="Return an empty collection rather than 'null'."
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#returnemptycollectionratherthannull">
+        <description>
+            For any method that returns an collection (such as an array, Collection or Map), it is better to return
+            an empty one rather than a null reference. This removes the need for null checking all results and avoids
+            inadvertent NullPointerExceptions.
+
+            See Effective Java, 3rd Edition, Item 54: Return empty collections or arrays instead of null
+        </description>
+        <priority>1</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration
+[
+(./ResultType/Type[pmd-java:typeIs('java.util.Collection') or pmd-java:typeIs('java.util.Map') or @ArrayType=true()])
+and
+(./Block/BlockStatement/Statement/ReturnStatement/Expression/PrimaryExpression/PrimaryPrefix/Literal/NullLiteral)
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Example {
+    // Not a good idea...
+    public int[] badBehavior() {
+        // ...
+        return null;
+    }
+
+    // Good behavior
+    public String[] bonnePratique() {
+        //...
+        return new String[0];
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="ReturnFromFinallyBlock"
+          language="java"
+          since="1.05"
+          message="Avoid returning from a finally block"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#returnfromfinallyblock">
+        <description>
+            Avoid returning from a finally block, this can discard exceptions.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>//FinallyStatement//ReturnStatement except //FinallyStatement//(MethodDeclaration|LambdaExpression)//ReturnStatement</value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Bar {
+    public String foo() {
+        try {
+            throw new Exception( "My Exception" );
+        } catch (Exception e) {
+            throw e;
+        } finally {
+            return "A. O. K."; // return not recommended here
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="SimpleDateFormatNeedsLocale"
+          language="java"
+          since="2.0"
+          message="When instantiating a SimpleDateFormat object, specify a Locale"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#simpledateformatneedslocale">
+        <description>
+            Be sure to specify a Locale when creating SimpleDateFormat instances to ensure that locale-appropriate
+            formatting is used.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//AllocationExpression
+ [ClassOrInterfaceType[@Image='SimpleDateFormat']]
+ [Arguments[@Size=1]]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+  // Should specify Locale.US (or whatever)
+  private SimpleDateFormat sdf = new SimpleDateFormat("pattern");
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="SingleMethodSingleton"
+          language="java"
+          since="5.4"
+          message="Class contains multiple getInstance methods. Please review."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.SingleMethodSingletonRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#singlemethodsingleton">
+        <description>
+            Some classes contain overloaded getInstance. The problem with overloaded getInstance methods
+            is that the instance created using the overloaded method is not cached and so,
+            for each call and new objects will be created for every invocation.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+public class Singleton {
+
+    private static Singleton singleton = new Singleton( );
+
+    private Singleton(){ }
+
+    public static Singleton getInstance( ) {
+        return singleton;
+    }
+
+    public static Singleton getInstance(Object obj){
+        Singleton singleton = (Singleton) obj;
+        return singleton;           //violation
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="SingletonClassReturningNewInstance"
+          language="java"
+          since="5.4"
+          message="getInstance method always creates a new object and hence does not comply to Singleton Design Pattern behaviour. Please review"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.SingletonClassReturningNewInstanceRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#singletonclassreturningnewinstance">
+        <description>
+            A singleton class should only ever have one instance. Failure to check
+            whether an instance has already been created may result in multiple
+            instances being created.
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+class Singleton {
+    private static Singleton instance = null;
+    public static Singleton getInstance() {
+        synchronized(Singleton.class) {
+            return new Singleton(); // this should be assigned to the field
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="StaticEJBFieldShouldBeFinal"
+          language="java"
+          since="4.1"
+          message="EJB's shouldn't have non-final static fields"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#staticejbfieldshouldbefinal">
+        <description>
+            According to the J2EE specification, an EJB should not have any static fields
+            with write access. However, static read-only fields are allowed. This ensures proper
+            behavior especially when instances are distributed by the container on several JREs.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration[
+    (
+    (./ImplementsList/ClassOrInterfaceType[ends-with(@Image,'SessionBean')])
+    or
+    (./ImplementsList/ClassOrInterfaceType[ends-with(@Image,'EJBHome')])
+    or
+    (./ImplementsList/ClassOrInterfaceType[ends-with(@Image,'EJBLocalObject')])
+    or
+    (./ImplementsList/ClassOrInterfaceType[ends-with(@Image,'EJBLocalHome')])
+    or
+    (./ExtendsList/ClassOrInterfaceType[ends-with(@Image,'EJBObject')])
+    )
+    and
+    (./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration[
+         (./FieldDeclaration[@Static = true()])
+         and
+         (./FieldDeclaration[@Final = false()])
+    ])
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class SomeEJB extends EJBObject implements EJBLocalHome {
+
+    private static int CountA;          // poor, field can be edited
+
+    private static final int CountB;    // preferred, read-only access
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="StringBufferInstantiationWithChar"
+          language="java"
+          since="3.9"
+          message="Do not instantiate a StringBuffer or StringBuilder with a char"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#stringbufferinstantiationwithchar">
+        <description>
+            Individual character values provided as initialization arguments will be converted into integers.
+            This can lead to internal buffer sizes that are larger than expected. Some examples:
+
+            ```
+            new StringBuffer()      //  16
+            new StringBuffer(6)     //  6
+            new StringBuffer("hello world")  // 11 + 16 = 27
+            new StringBuffer('A')   //  chr(A) = 65
+            new StringBuffer("A")   //  1 + 16 = 17
+
+            new StringBuilder()     //  16
+            new StringBuilder(6)    //  6
+            new StringBuilder("hello world")  // 11 + 16 = 27
+            new StringBuilder('C')   //  chr(C) = 67
+            new StringBuilder("A")   //  1 + 16 = 17
+            ```
+        </description>
+        <priority>4</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//AllocationExpression/ClassOrInterfaceType
+[@Image='StringBuffer' or @Image='StringBuilder']
+/../Arguments/ArgumentList/Expression/PrimaryExpression
+/PrimaryPrefix/
+Literal
+  [starts-with(@Image, "'")]
+  [ends-with(@Image, "'")]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+// misleading instantiation, these buffers
+// are actually sized to 99 characters long
+StringBuffer  sb1 = new StringBuffer('c');
+StringBuilder sb2 = new StringBuilder('c');
+
+// in these forms, just single characters are allocated
+StringBuffer  sb3 = new StringBuffer("c");
+StringBuilder sb4 = new StringBuilder("c");
+]]>
+        </example>
+    </rule>
+
+    <rule name="SuspiciousEqualsMethodName"
+          language="java"
+          since="2.0"
+          message="The method name and parameter number are suspiciously close to equals(Object)"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#suspiciousequalsmethodname">
+        <description>
+            The method name and parameter number are suspiciously close to `Object.equals`, which can denote an
+            intention to override it. However, the method does not override `Object.equals`, but overloads it instead.
+            Overloading `Object.equals` method is confusing for other programmers, error-prone and hard to maintain,
+            especially when using inheritance, because `@Override` annotations used in subclasses can provide a false
+            sense of security. For more information on `Object.equals` method, see Effective Java, 3rd Edition,
+            Item 10: Obey the general contract when overriding equals.
+        </description>
+        <priority>2</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//MethodDeclaration[@Name = 'equals']
+[
+    (@Arity = 1
+    and not (MethodDeclarator/FormalParameters/FormalParameter/Type/ReferenceType/ClassOrInterfaceType
+        [@Image = 'Object' or @Image = 'java.lang.Object'])
+    or not (ResultType/Type/PrimitiveType[@Image = 'boolean'])
+    )  or  (
+    @Arity = 2
+    and ResultType/Type/PrimitiveType[@Image = 'boolean']
+    and MethodDeclarator/FormalParameters//ClassOrInterfaceType[@Image = 'Object' or @Image = 'java.lang.Object']
+    and not(../Annotation/MarkerAnnotation/Name[@Image='Override'])
+    )
+]
+| //MethodDeclaration[@Name = 'equal']
+[
+    @Arity = 1
+    and MethodDeclarator/FormalParameters/FormalParameter/Type/ReferenceType/ClassOrInterfaceType
+        [@Image = 'Object' or @Image = 'java.lang.Object']
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+   public int equals(Object o) {
+     // oops, this probably was supposed to be boolean equals
+   }
+   public boolean equals(String s) {
+     // oops, this probably was supposed to be equals(Object)
+   }
+   public boolean equals(Object o1, Object o2) {
+     // oops, this probably was supposed to be equals(Object)
+   }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="SuspiciousHashcodeMethodName"
+          language="java"
+          since="1.5"
+          message="The method name and return type are suspiciously close to hashCode()"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.SuspiciousHashcodeMethodNameRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#suspicioushashcodemethodname">
+        <description>
+            The method name and return type are suspiciously close to hashCode(), which may denote an intention
+            to override the hashCode() method.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public class Foo {
+    public int hashcode() { // oops, this probably was supposed to be 'hashCode'
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="SuspiciousOctalEscape"
+          language="java"
+          since="1.5"
+          message="Suspicious decimal characters following octal escape in string literal"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.SuspiciousOctalEscapeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#suspiciousoctalescape">
+        <description>
+            A suspicious octal escape sequence was found inside a String literal.
+            The Java language specification (section 3.10.6) says an octal
+            escape sequence inside a literal String shall consist of a backslash
+            followed by:
+
+            OctalDigit | OctalDigit OctalDigit | ZeroToThree OctalDigit OctalDigit
+
+            Any octal escape sequence followed by non-octal digits can be confusing,
+            e.g. "\038" is interpreted as the octal escape sequence "\03" followed by
+            the literal character "8".
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public void foo() {
+  // interpreted as octal 12, followed by character '8'
+  System.out.println("suspicious: \128");
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="TestClassWithoutTestCases"
+          language="java"
+          since="3.0"
+          message="This class name ends with 'Test' but contains no test cases"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.TestClassWithoutTestCasesRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#testclasswithouttestcases">
+        <description>
+            Test classes end with the suffix Test. Having a non-test class with that name is not a good practice,
+            since most people will assume it is a test case. Test classes have test methods named testXXX.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+//Consider changing the name of the class if it is not a test
+//Consider adding test methods if it is a test
+public class CarTest {
+   public static void main(String[] args) {
+    // do something
+   }
+   // code
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="UnconditionalIfStatement"
+          language="java"
+          since="1.5"
+          message="Do not use 'if' statements that are always true or always false"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#unconditionalifstatement">
+        <description>
+            Do not use "if" statements whose conditionals are always true or always false.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//IfStatement/Expression
+ [count(PrimaryExpression)=1]
+ /PrimaryExpression/PrimaryPrefix/Literal/BooleanLiteral
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Foo {
+    public void close() {
+        if (true) {        // fixed conditional, not recommended
+            // ...
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="UnnecessaryBooleanAssertion"
+          language="java"
+          since="3.0"
+          message="assertTrue(true) or similar statements are unnecessary"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          typeResolution="true"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#unnecessarybooleanassertion">
+        <description>
+            A JUnit test assertion with a boolean literal is unnecessary since it always will evaluate to the same thing.
+            Consider using flow control (in case of assertTrue(false) or similar) or simply removing
+            statements like assertTrue(true) and assertFalse(false).  If you just want a test to halt after finding
+            an error, use the fail() method and provide an indication message of why it did.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//ClassOrInterfaceDeclaration[
+    pmd-java:typeIs('junit.framework.TestCase')
+    or .//MarkerAnnotation/Name[
+        pmd-java:typeIs('org.junit.Test')
+        or pmd-java:typeIs('org.junit.jupiter.api.Test')
+        or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
+        or pmd-java:typeIs('org.junit.jupiter.api.TestFactory')
+        or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
+        or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')
+        ]
+    ]
+//StatementExpression
+[
+    PrimaryExpression/PrimaryPrefix/Name[@Image='assertTrue' or  @Image='assertFalse']
+    and
+    PrimaryExpression/PrimarySuffix/Arguments/ArgumentList/Expression[
+        PrimaryExpression/PrimaryPrefix/Literal/BooleanLiteral
+        or
+        UnaryExpressionNotPlusMinus[@Image='!']
+            /PrimaryExpression/PrimaryPrefix[Literal/BooleanLiteral or Name[count(../../*)=1]]
+    ]
+]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class SimpleTest extends TestCase {
+    public void testX() {
+        assertTrue(true);       // serves no real purpose
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="UnnecessaryCaseChange"
+          language="java"
+          since="3.3"
+          message="Using equalsIgnoreCase() is cleaner than using toUpperCase/toLowerCase().equals()."
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.UnnecessaryCaseChangeRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#unnecessarycasechange">
+        <description>
+            Using equalsIgnoreCase() is faster than using toUpperCase/toLowerCase().equals()
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+boolean answer1 = buz.toUpperCase().equals("baz");              // should be buz.equalsIgnoreCase("baz")
+
+boolean answer2 = buz.toUpperCase().equalsIgnoreCase("baz");    // another unnecessary toUpperCase()
+]]>
+        </example>
+    </rule>
+
+    <rule name="UnnecessaryConversionTemporary"
+          language="java"
+          since="0.1"
+          message="Avoid unnecessary temporaries when converting primitives to Strings"
+          class="net.sourceforge.pmd.lang.java.rule.errorprone.UnnecessaryConversionTemporaryRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#unnecessaryconversiontemporary">
+        <description>
+            Avoid the use temporary objects when converting primitives to Strings. Use the static conversion methods
+            on the wrapper classes instead.
+        </description>
+        <priority>3</priority>
+        <example>
+            <![CDATA[
+public String convert(int x) {
+    String foo = new Integer(x).toString(); // this wastes an object
+
+    return Integer.toString(x);             // preferred approach
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="UnusedNullCheckInEquals"
+          language="java"
+          since="3.5"
+          message="Invoke equals() on the object you''ve already ensured is not null"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#unusednullcheckinequals">
+        <description>
+            After checking an object reference for null, you should invoke equals() on that object rather than passing it to another object's equals() method.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+(//PrimaryPrefix[ends-with(Name/@Image, '.equals') and Name/@Image != 'Arrays.equals'] | //PrimarySuffix[@Image='equals' and not(../PrimaryPrefix/Literal)])
+ /following-sibling::PrimarySuffix/Arguments/ArgumentList/Expression
+ /PrimaryExpression[not(PrimarySuffix)]/PrimaryPrefix
+ /Name[@Image = ./../../../../../../../../../../Expression/ConditionalAndExpression
+ /EqualityExpression[@Image="!=" and not(./preceding-sibling::*) and
+ ./PrimaryExpression/PrimaryPrefix/Literal/NullLiteral]
+  /PrimaryExpression/PrimaryPrefix/Name/@Image]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Test {
+
+    public String method1() { return "ok";}
+    public String method2() { return null;}
+
+    public void method(String a) {
+        String b;
+        // I don't know it method1() can be "null"
+        // but I know "a" is not null..
+        // I'd better write a.equals(method1())
+
+        if (a!=null && method1().equals(a)) { // will trigger the rule
+            //whatever
+        }
+
+        if (method1().equals(a) && a != null) { // won't trigger the rule
+            //whatever
+        }
+
+        if (a!=null && method1().equals(b)) { // won't trigger the rule
+            //whatever
+        }
+
+        if (a!=null && "LITERAL".equals(a)) { // won't trigger the rule
+            //whatever
+        }
+
+        if (a!=null && !a.equals("go")) { // won't trigger the rule
+            a=method2();
+            if (method1().equals(a)) {
+                //whatever
+            }
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="UseCorrectExceptionLogging"
+          language="java"
+          since="3.2"
+          message="Use the correct logging statement for logging exceptions"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#usecorrectexceptionlogging">
+        <description>
+            To make sure the full stacktrace is printed out, use the logging statement with two arguments: a String and a Throwable.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//CatchStatement/Block/BlockStatement/Statement/StatementExpression
+    /PrimaryExpression
+        [PrimaryPrefix/Name
+            [starts-with(@Image,
+             concat((ancestor::ClassOrInterfaceDeclaration/ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/FieldDeclaration
+                [Type//ClassOrInterfaceType[@Image='Log']]
+                /VariableDeclarator/VariableDeclaratorId/@Name)[1], '.'))
+            ]
+        ]
+        [PrimarySuffix/Arguments[@Size= 1]]
+        [PrimarySuffix/Arguments//Name/@Image = ancestor::CatchStatement/FormalParameter/VariableDeclaratorId/@Name]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public class Main {
+    private static final Log _LOG = LogFactory.getLog( Main.class );
+    void bar() {
+        try {
+        } catch( Exception e ) {
+            _LOG.error( e ); //Wrong!
+        } catch( OtherException oe ) {
+            _LOG.error( oe.getMessage(), oe ); //Correct
+        }
+    }
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="UseEqualsToCompareStrings"
+          language="java"
+          since="4.1"
+          message="Use equals() to compare strings instead of ''=='' or ''!=''"
+          class="net.sourceforge.pmd.lang.rule.XPathRule"
+          externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#useequalstocomparestrings">
+        <description>
+            Using '==' or '!=' to compare strings only works if intern version is used on both sides.
+            Use the equals() method instead.
+        </description>
+        <priority>3</priority>
+        <properties>
+            <property name="version" value="2.0"/>
+            <property name="xpath">
+                <value>
+                    <![CDATA[
+//EqualityExpression
+    [count(PrimaryExpression[pmd-java:typeIs('java.lang.String')]) = 2]
+]]>
+                </value>
+            </property>
+        </properties>
+        <example>
+            <![CDATA[
+public boolean test(String s) {
+    if (s == "one") return true;        // unreliable
+    if ("two".equals(s)) return true;   // better
+    return false;
+}
+]]>
+        </example>
+    </rule>
+
+    <rule name="UselessOperationOnImmutable"

Review comment:
       This rule is enabled in our repo




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