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Posted to notifications@ignite.apache.org by GitBox <gi...@apache.org> on 2021/09/09 13:56:08 UTC
[GitHub] [ignite-3] alievmirza opened a new pull request #327: review pmd check rules
alievmirza opened a new pull request #327:
URL: https://github.com/apache/ignite-3/pull/327
Let's select rules that we want to add to our `check-rules/pmd-rules.xml`.
I propose to review at least ruels with `<priority>1</priority>` and `<priority>2</priority>`
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[GitHub] [ignite-3] alievmirza commented on a change in pull request #327: review pmd check rules
Posted by GitBox <gi...@apache.org>.
alievmirza commented on a change in pull request #327:
URL: https://github.com/apache/ignite-3/pull/327#discussion_r705400378
##########
File path: check-rules/bestpractices.xml
##########
@@ -0,0 +1,2130 @@
+<?xml version="1.0"?>
+
+<ruleset name="Best Practices"
+ 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 which enforce generally accepted best practices.
+ </description>
+
+ <rule name="AbstractClassWithoutAbstractMethod"
+ language="java"
+ since="3.0"
+ message="This abstract class does not have any abstract methods"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AbstractClassWithoutAbstractMethodRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#abstractclasswithoutabstractmethod">
+ <description>
+ The abstract class does not contain any abstract methods. An abstract class suggests
+ an incomplete implementation, which is to be completed by subclasses implementing the
+ abstract methods. If the class is intended to be used as a base class only (not to be instantiated
+ directly) a protected constructor can be provided prevent direct instantiation.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public abstract class Foo {
+ void int method1() { ... }
+ void int method2() { ... }
+ // consider using abstract methods or removing
+ // the abstract modifier and adding protected constructors
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AccessorClassGeneration"
+ language="java"
+ since="1.04"
+ maximumLanguageVersion="10"
+ message="Avoid instantiation through private constructors from outside of the constructor's class."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AccessorClassGenerationRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#accessorclassgeneration">
+ <description>
+ Instantiation by way of private constructors from outside of the constructor's class often causes the
+ generation of an accessor. A factory method, or non-privatization of the constructor can eliminate this
+ situation. The generated class file is actually an interface. It gives the accessing class the ability
+ to invoke a new hidden package scope constructor that takes the interface as a supplementary parameter.
+ This turns a private constructor effectively into one with package scope, and is challenging to discern.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Outer {
+ void method(){
+ Inner ic = new Inner();//Causes generation of accessor class
+ }
+ public class Inner {
+ private Inner(){}
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AccessorMethodGeneration"
+ language="java"
+ since="5.5.4"
+ maximumLanguageVersion="10"
+ message="Avoid autogenerated methods to access private fields and methods of inner / outer classes"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AccessorMethodGenerationRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#accessormethodgeneration">
+ <description>
+ When accessing private fields / methods from another class, the Java compiler will generate accessor methods
+ with package-private visibility. This adds overhead, and to the dex method count on Android. This situation can
+ be avoided by changing the visibility of the field / method from private to package-private.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class OuterClass {
+ private int counter;
+ /* package */ int id;
+ public class InnerClass {
+ InnerClass() {
+ OuterClass.this.counter++; // wrong accessor method will be generated
+ }
+ public int getOuterClassId() {
+ return OuterClass.this.id; // id is package-private, no accessor method needed
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ArrayIsStoredDirectly"
+ language="java"
+ since="2.2"
+ message="The user-supplied array ''{0}'' is stored directly."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.ArrayIsStoredDirectlyRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#arrayisstoreddirectly">
+ <description>
+ Constructors and methods receiving arrays should clone objects and store the copy.
+ This prevents future changes from the user from affecting the original array.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ private String [] x;
+ public void foo (String [] param) {
+ // Don't do this, make a copy of the array at least
+ this.x=param;
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidMessageDigestField"
+ language="java"
+ since="6.18.0"
+ message="You shouldn't declare field of MessageDigest type, because unsynchronized access could cause problems"
+ typeResolution="true"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidmessagedigestfield">
+ <description>
+ Declaring a MessageDigest instance as a field make this instance directly available to multiple threads.
+ Such sharing of MessageDigest instances should be avoided if possible since it leads to wrong results
+ if the access is not synchronized correctly.
+ Just create a new instance and use it locally, where you need it.
+ Creating a new instance is easier than synchronizing access to a shared instance.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//FieldDeclaration[pmd-java:typeIs('java.security.MessageDigest')]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+import java.security.MessageDigest;
+public class AvoidMessageDigestFieldExample {
+ private final MessageDigest sharedMd;
+ public AvoidMessageDigestFieldExample() throws Exception {
+ sharedMd = MessageDigest.getInstance("SHA-256");
+ }
+ public byte[] calculateHashShared(byte[] data) {
+ // sharing a MessageDigest like this without synchronizing access
+ // might lead to wrong results
+ sharedMd.reset();
+ sharedMd.update(data);
+ return sharedMd.digest();
+ }
+ // better
+ public byte[] calculateHash(byte[] data) throws Exception {
+ MessageDigest md = MessageDigest.getInstance("SHA-256");
+ md.update(data);
+ return md.digest();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidPrintStackTrace"
+ language="java"
+ since="3.2"
+ message="Avoid printStackTrace(); use a logger call instead."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidprintstacktrace">
+ <description>
+ Avoid printStackTrace(); use a logger call instead.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//PrimaryExpression[
+ ( PrimaryPrefix[Name[contains(@Image,'printStackTrace')]]
+ | PrimarySuffix[@Image='printStackTrace']
+ )/following-sibling::*[1][self::PrimarySuffix/Arguments[@Size=0]]
+]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+class Foo {
+ void bar() {
+ try {
+ // do something
+ } catch (Exception e) {
+ e.printStackTrace();
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidReassigningCatchVariables"
+ language="java"
+ since="6.27.0"
+ message="Avoid reassigning caught exception ''{0}''"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AvoidReassigningCatchVariablesRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidreassigningcatchvariables">
+ <description>
+ Reassigning exception variables caught in a catch statement should be avoided because of:
+
+ 1) If it is needed, multi catch can be easily added and code will still compile.
+
+ 2) Following the principle of least surprise we want to make sure that a variable caught in a catch statement
+ is always the one thrown in a try block.
+ </description>
+ <priority>3</priority>
+ <example><![CDATA[
+public class Foo {
+ public void foo() {
+ try {
+ // do something
+ } catch (Exception e) {
+ e = new NullPointerException(); // not recommended
+ }
+ try {
+ // do something
+ } catch (MyException | ServerException e) {
+ e = new RuntimeException(); // won't compile
+ }
+ }
+}
+ ]]></example>
+ </rule>
+
+ <rule name="AvoidReassigningLoopVariables"
+ language="java"
+ since="6.11.0"
+ message="Avoid reassigning the loop control variable ''{0}''"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AvoidReassigningLoopVariablesRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidreassigningloopvariables">
+ <description>
+ Reassigning loop variables can lead to hard-to-find bugs. Prevent or limit how these variables can be changed.
+
+ In foreach-loops, configured by the `foreachReassign` property:
+ - `deny`: Report any reassignment of the loop variable in the loop body. _This is the default._
+ - `allow`: Don't check the loop variable.
+ - `firstOnly`: Report any reassignments of the loop variable, except as the first statement in the loop body.
+ _This is useful if some kind of normalization or clean-up of the value before using is permitted, but any other change of the variable is not._
+
+ In for-loops, configured by the `forReassign` property:
+ - `deny`: Report any reassignment of the control variable in the loop body. _This is the default._
+ - `allow`: Don't check the control variable.
+ - `skip`: Report any reassignments of the control variable, except conditional increments/decrements (`++`, `--`, `+=`, `-=`).
+ _This prevents accidental reassignments or unconditional increments of the control variable._
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ private void foo() {
+ for (String s : listOfStrings()) {
+ s = s.trim(); // OK, when foreachReassign is "firstOnly" or "allow"
+ doSomethingWith(s);
+ s = s.toUpper(); // OK, when foreachReassign is "allow"
+ doSomethingElseWith(s);
+ }
+ for (int i=0; i < 10; i++) {
+ if (check(i)) {
+ i++; // OK, when forReassign is "skip" or "allow"
+ }
+ i = 5; // OK, when forReassign is "allow"
+ doSomethingWith(i);
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidReassigningParameters"
+ language="java"
+ since="1.0"
+ message="Avoid reassigning parameters such as ''{0}''"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AvoidReassigningParametersRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidreassigningparameters">
+ <description>
+ Reassigning values to incoming parameters of a method or constructor is not recommended, as this can
+ make the code more difficult to understand. The code is often read with the assumption that parameter values
+ don't change and an assignment violates therefore the principle of least astonishment. This is especially a
+ problem if the parameter is documented e.g. in the method's javadoc and the new content differs from the original
+ documented content.
+
+ Use temporary local variables instead. This allows you to assign a new name, which makes the code better
+ understandable.
+
+ Note that this rule considers both methods and constructors. If there are multiple assignments for a formal
+ parameter, then only the first assignment is reported.
+ </description>
+ <priority>2</priority>
+ <example>
+ <![CDATA[
+public class Hello {
+ private void greet(String name) {
+ name = name.trim();
+ System.out.println("Hello " + name);
+ // preferred
+ String trimmedName = name.trim();
+ System.out.println("Hello " + trimmedName);
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidStringBufferField"
+ language="java"
+ since="4.2"
+ message="StringBuffers can grow quite a lot, and so may become a source of memory leak (if the owning class has a long life time)."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidstringbufferfield">
+ <description>
+ StringBuffers/StringBuilders can grow considerably, and so may become a source of memory leaks
+ if held within objects with long lifetimes.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//FieldDeclaration/Type/ReferenceType/ClassOrInterfaceType[@Image = 'StringBuffer' or @Image = 'StringBuilder']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo {
+ private StringBuffer buffer; // potential memory leak as an instance variable;
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidUsingHardCodedIP"
+ language="java"
+ since="4.1"
+ message="Do not hard code the IP address ${variableName}"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AvoidUsingHardCodedIPRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidusinghardcodedip">
+ <description>
+ Application with hard-coded IP addresses can become impossible to deploy in some cases.
+ Externalizing IP adresses is preferable.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ private String ip = "127.0.0.1"; // not recommended
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="CheckResultSet"
+ language="java"
+ since="4.1"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.CheckResultSetRule"
+ message="Always check the return of one of the navigation method (next,previous,first,last) of a ResultSet."
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#checkresultset">
+ <description>
+ Always check the return values of navigation methods (next, previous, first, last) of a ResultSet.
+ If the value return is 'false', it should be handled properly.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+Statement stat = conn.createStatement();
+ResultSet rst = stat.executeQuery("SELECT name FROM person");
+rst.next(); // what if it returns false? bad form
+String firstName = rst.getString(1);
+Statement stat = conn.createStatement();
+ResultSet rst = stat.executeQuery("SELECT name FROM person");
+if (rst.next()) { // result is properly examined and used
+ String firstName = rst.getString(1);
+ } else {
+ // handle missing data
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ConstantsInInterface"
+ language="java"
+ since="5.5"
+ message="Avoid constants in interfaces. Interfaces define types, constants are implementation details better placed in classes or enums. See Effective Java, item 19."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#constantsininterface">
+ <description>
+ Avoid constants in interfaces. Interfaces should define types, constants are implementation details
+ better placed in classes or enums. See Effective Java, item 19.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="ignoreIfHasMethods" type="Boolean" description="Whether to ignore constants in interfaces if the interface defines any methods" value="true"/>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceDeclaration[@Interface= true()][$ignoreIfHasMethods= false() or not(.//MethodDeclaration)]//FieldDeclaration
+ ]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public interface ConstantInterface {
+ public static final int CONST1 = 1; // violation, no fields allowed in interface!
+ static final int CONST2 = 1; // violation, no fields allowed in interface!
+ final int CONST3 = 1; // violation, no fields allowed in interface!
+ int CONST4 = 1; // violation, no fields allowed in interface!
+}
+// with ignoreIfHasMethods = false
+public interface AnotherConstantInterface {
+ public static final int CONST1 = 1; // violation, no fields allowed in interface!
+ int anyMethod();
+}
+// with ignoreIfHasMethods = true
+public interface YetAnotherConstantInterface {
+ public static final int CONST1 = 1; // no violation
+ int anyMethod();
+}
+ ]]>
+ </example>
+ </rule>
+
+ <rule name="DefaultLabelNotLastInSwitchStmt"
+ language="java"
+ since="1.5"
+ message="The default label should be the last label in a switch statement"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#defaultlabelnotlastinswitchstmt">
+ <description>
+ By convention, the default label should be the last label in a switch statement.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//SwitchStatement
+ [not(SwitchLabel[position() = last()][@Default= true()])]
+ [SwitchLabel[@Default= true()]]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo {
+ void bar(int a) {
+ switch (a) {
+ case 1: // do something
+ break;
+ default: // the default case should be last, by convention
+ break;
+ case 2:
+ break;
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="DoubleBraceInitialization"
+ language="java"
+ since="6.16.0"
+ message="Double-brace initialization should be avoided"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#doublebraceinitialization">
+ <description>
+ Double brace initialisation is a pattern to initialise eg collections concisely. But it implicitly
+ generates a new .class file, and the object holds a strong reference to the enclosing object. For those
+ reasons, it is preferable to initialize the object normally, even though it's verbose.
+
+ This rule counts any anonymous class which only has a single initializer as an instance of double-brace
+ initialization. There is currently no way to find out whether a method called in the initializer is not
+ accessible from outside the anonymous class, and those legit cases should be suppressed for the time being.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//AllocationExpression/ClassOrInterfaceBody[count(*)=1]/*/Initializer[@Static=false()]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example><![CDATA[
+// this is double-brace initialization
+return new ArrayList<String>(){{
+ add("a");
+ add("b");
+ add("c");
+}};
+// the better way is to not create an anonymous class:
+List<String> a = new ArrayList<>();
+a.add("a");
+a.add("b");
+a.add("c");
+return a;
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="ForLoopCanBeForeach"
+ language="java"
+ since="6.0.0"
+ message="This 'for' loop can be replaced by a 'foreach' loop"
+ typeResolution="true"
+ minimumLanguageVersion="1.5"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.ForLoopCanBeForeachRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#forloopcanbeforeach">
+ <description>
+ Reports loops that can be safely replaced with the foreach syntax. The rule considers loops over
+ lists, arrays and iterators. A loop is safe to replace if it only uses the index variable to
+ access an element of the list or array, only has one update statement, and loops through *every*
+ element of the list or array left to right.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class MyClass {
+ void loop(List<String> l) {
+ for (int i = 0; i < l.size(); i++) { // pre Java 1.5
+ System.out.println(l.get(i));
+ }
+ for (String s : l) { // post Java 1.5
+ System.out.println(s);
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ForLoopVariableCount"
+ language="java"
+ since="6.11.0"
+ message="Too many control variables in the 'for' statement"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#forloopvariablecount">
+ <description>
+ Having a lot of control variables in a 'for' loop makes it harder to see what range of values
+ the loop iterates over. By default this rule allows a regular 'for' loop with only one variable.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="maximumVariables" type="Integer"
+ description="A regular for statement will have 1 control variable" min="0" max="100" value="1"/>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>//ForInit/LocalVariableDeclaration[count(VariableDeclarator) > $maximumVariables]</value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+// this will be reported with the default setting of at most one control variable in a for loop
+for (int i = 0, j = 0; i < 10; i++, j += 2) {
+ foo();
+]]>
+ </example>
+ </rule>
+
+ <rule name="GuardLogStatement"
+ language="java"
+ since="5.1.0"
+ message="Logger calls should be surrounded by log level guards."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.GuardLogStatementRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#guardlogstatement">
+ <description>
+ Whenever using a log level, one should check if the loglevel is actually enabled, or
+ otherwise skip the associate String creation and manipulation.
+
+ An alternative to checking the log level are substituting parameters, formatters or lazy logging
+ with lambdas. The available alternatives depend on the actual logging framework.
+ </description>
+ <priority>2</priority>
+ <example>
+ <![CDATA[
+// Add this for performance
+if (log.isDebugEnabled()) {
+ log.debug("log something" + param1 + " and " + param2 + "concat strings");
+}
+// Avoid the guarding if statement with substituting parameters
+log.debug("log something {} and {}", param1, param2);
+// Avoid the guarding if statement with formatters
+log.debug("log something %s and %s", param1, param2);
+// Avoid the guarding if statement with lazy logging and lambdas
+log.debug("log something expensive: {}", () -> calculateExpensiveLoggingText());
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit4SuitesShouldUseSuiteAnnotation"
+ language="java"
+ since="4.0"
+ message="JUnit 4 indicates test suites via annotations, not the suite method."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit4suitesshouldusesuiteannotation">
+ <description>
+ In JUnit 3, test suites are indicated by the suite() method. In JUnit 4, suites are indicated
+ through the @RunWith(Suite.class) annotation.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceBodyDeclaration
+[MethodDeclaration[@Name='suite']/ResultType/Type/ReferenceType/ClassOrInterfaceType[pmd-java:typeIs('junit.framework.Test')]]
+[not(MethodDeclaration/Block/BlockStatement/Statement/ReturnStatement//ClassOrInterfaceType[pmd-java:typeIs('junit.framework.JUnit4TestAdapter')])]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class BadExample extends TestCase{
+ public static Test suite(){
+ return new Suite();
+ }
+}
+@RunWith(Suite.class)
+@SuiteClasses( { TestOne.class, TestTwo.class })
+public class GoodTest {
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit4TestShouldUseAfterAnnotation"
+ language="java"
+ since="4.0"
+ message="JUnit 4 tests that clean up tests should use the @After annotation, JUnit5 tests should use @AfterEach or @AfterAll"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit4testshoulduseafterannotation">
+ <description>
+ In JUnit 3, the tearDown method was used to clean up all data entities required in running tests.
+ JUnit 4 skips the tearDown method and executes all methods annotated with @After after running each test.
+ JUnit 5 introduced @AfterEach and @AfterAll annotations to execute methods after each test or after all tests in the class, respectively.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceBodyDeclaration
+ [MethodDeclaration[@Name='tearDown']]
+ [not(Annotation/*/Name[
+ pmd-java:typeIs('org.junit.After')
+ or pmd-java:typeIs('org.junit.jupiter.api.AfterEach')
+ or pmd-java:typeIs('org.junit.jupiter.api.AfterAll')
+ or pmd-java:typeIs('org.testng.annotations.AfterMethod')])]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class MyTest {
+ public void tearDown() {
+ bad();
+ }
+}
+public class MyTest2 {
+ @After public void tearDown() {
+ good();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit4TestShouldUseBeforeAnnotation"
+ language="java"
+ since="4.0"
+ message="JUnit 4 tests that set up tests should use the @Before annotation, JUnit5 tests should use @BeforeEach or @BeforeAll"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit4testshouldusebeforeannotation">
+ <description>
+ In JUnit 3, the setUp method was used to set up all data entities required in running tests.
+ JUnit 4 skips the setUp method and executes all methods annotated with @Before before all tests.
+ JUnit 5 introduced @BeforeEach and @BeforeAll annotations to execute methods before each test or before all tests in the class, respectively.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceBodyDeclaration
+ [MethodDeclaration[@Name='setUp']]
+ [not(Annotation/*/Name[
+ pmd-java:typeIs('org.junit.Before')
+ or pmd-java:typeIs('org.junit.jupiter.api.BeforeEach')
+ or pmd-java:typeIs('org.junit.jupiter.api.BeforeAll')
+ or pmd-java:typeIs('org.testng.annotations.BeforeMethod')])]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class MyTest {
+ public void setUp() {
+ bad();
+ }
+}
+public class MyTest2 {
+ @Before public void setUp() {
+ good();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit4TestShouldUseTestAnnotation"
+ language="java"
+ since="4.0"
+ message="JUnit 4 tests that execute tests should use the @Test annotation, JUnit 5 tests should use @Test, @RepeatedTest, @TestFactory, @TestTemplate or @ParameterizedTest"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit4testshouldusetestannotation">
+ <description>
+ In JUnit 3, the framework executed all methods which started with the word test as a unit test.
+ In JUnit 4, only methods annotated with the @Test annotation are executed.
+ In JUnit 5, one of the following annotations should be used for tests: @Test, @RepeatedTest, @TestFactory, @TestTemplate or @ParameterizedTest.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceDeclaration[
+ matches(@SimpleName, $testClassPattern)
+ or ExtendsList/ClassOrInterfaceType[pmd-java:typeIs('junit.framework.TestCase')]]
+ /ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration[MethodDeclaration[@Public=true() and starts-with(@Name, 'test')]]
+ [not(Annotation//Name[
+ pmd-java:typeIs('org.junit.Test')
+ or pmd-java:typeIs('org.junit.jupiter.api.Test') or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
+ or pmd-java:typeIs('org.junit.jupiter.api.TestFactory') or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
+ or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')
+ ])]
+]]>
+ </value>
+ </property>
+ <property name="testClassPattern" type="Regex" description="The regex pattern used to identify test classes" value="Test" />
+ <property name="version" value="2.0"/>
+ </properties>
+ <example>
+ <![CDATA[
+public class MyTest {
+ public void testBad() {
+ doSomething();
+ }
+ @Test
+ public void testGood() {
+ doSomething();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit5TestShouldBePackagePrivate"
+ language="java"
+ since="6.35.0"
+ message="JUnit 5 tests should be package-private."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit5testshouldbepackageprivate">
+ <description><![CDATA[
+Reports JUnit 5 test classes and methods that are not package-private.
+Contrary to JUnit 4 tests, which required public visibility to be run by the engine,
+JUnit 5 tests can also be run if they're package-private. Marking them as such
+is a good practice to limit their visibility.
+Test methods are identified as those which use `@Test`, `@RepeatedTest`,
+`@TestFactory`, `@TestTemplate` or `@ParameterizedTest`.
+ ]]></description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceDeclaration[
+ (: a Junit 5 test class, ie, it has methods with the annotation :)
+ @Interface=false() and
+ ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration
+ [Annotation//Name[
+ 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')
+ ]]
+ [MethodDeclaration]
+]/(
+ self::*[@Abstract=false() and (@Public=true() or @Protected=true())]
+| ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration
+ [Annotation//Name[
+ 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')
+ ]]
+ /MethodDeclaration[@Public=true() or @Protected=true()]
+)
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+class MyTest { // not public, that's fine
+ @Test
+ public void testBad() { } // should not have a public modifier
+ @Test
+ protected void testAlsoBad() { } // should not have a protected modifier
+ @Test
+ private void testNoRun() { } // should not have a private modifier
+ @Test
+ void testGood() { } // package private as expected
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnitAssertionsShouldIncludeMessage"
+ language="java"
+ since="1.04"
+ message="JUnit assertions should include a message"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.JUnitAssertionsShouldIncludeMessageRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junitassertionsshouldincludemessage">
+ <description>
+ JUnit assertions should include an informative message - i.e., use the three-argument version of
+ assertEquals(), not the two-argument version.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo extends TestCase {
+ public void testSomething() {
+ assertEquals("foo", "bar");
+ // Use the form:
+ // assertEquals("Foo does not equals bar", "foo", "bar");
+ // instead
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnitTestContainsTooManyAsserts"
+ language="java"
+ since="5.0"
+ message="Unit tests should not contain more than ${maximumAsserts} assert(s)."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junittestcontainstoomanyasserts">
+ <description>
+ Unit tests should not contain too many asserts. Many asserts are indicative of a complex test, for which
+ it is harder to verify correctness. Consider breaking the test scenario into multiple, shorter test scenarios.
+ Customize the maximum number of assertions used by this Rule to suit your needs.
+
+ This rule checks for JUnit4, JUnit5 and TestNG Tests, as well as methods starting with "test".
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="maximumAsserts" type="Integer" min="1" max="1000" description="Maximum number of Asserts in a test method" value="1"/>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//MethodDeclaration[@Name[matches(.,'^test')] or ../Annotation/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')
+ or pmd-java:typeIs('org.testng.annotations.Test')
+ ]]
+ [count(.//PrimaryPrefix/Name[@Image[matches(.,'^assert')]]) > $maximumAsserts]
+]]>
+ </value>
+ </property>
+ <property name="version" value="2.0"/>
+ </properties>
+ <example>
+ <![CDATA[
+public class MyTestCase extends TestCase {
+ // Ok
+ public void testMyCaseWithOneAssert() {
+ boolean myVar = false;
+ assertFalse("should be false", myVar);
+ }
+ // Bad, too many asserts (assuming max=1)
+ public void testMyCaseWithMoreAsserts() {
+ boolean myVar = false;
+ assertFalse("myVar should be false", myVar);
+ assertEquals("should equals false", false, myVar);
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnitTestsShouldIncludeAssert"
+ language="java"
+ since="2.0"
+ message="JUnit tests should include assert() or fail()"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.JUnitTestsShouldIncludeAssertRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junittestsshouldincludeassert">
+ <description>
+ JUnit tests should include at least one assertion. This makes the tests more robust, and using assert
+ with messages provide the developer a clearer idea of what the test does.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo extends TestCase {
+ public void testSomething() {
+ Bar b = findBar();
+ // This is better than having a NullPointerException
+ // assertNotNull("bar not found", b);
+ b.work();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnitUseExpected"
+ language="java"
+ since="4.0"
+ message="In JUnit4, use the @Test(expected) annotation to denote tests that should throw exceptions"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.JUnitUseExpectedRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junituseexpected">
+ <description>
+ In JUnit4, use the @Test(expected) annotation to denote tests that should throw exceptions.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class MyTest {
+ @Test
+ public void testBad() {
+ try {
+ doSomething();
+ fail("should have thrown an exception");
+ } catch (Exception e) {
+ }
+ }
+ @Test(expected=Exception.class)
+ public void testGood() {
+ doSomething();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="LiteralsFirstInComparisons"
+ language="java"
+ since="6.24.0"
+ message="Position literals first in String comparisons"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.LiteralsFirstInComparisonsRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#literalsfirstincomparisons">
+ <description>
+ Position literals first in all String comparisons, if the second argument is null then NullPointerExceptions
+ can be avoided, they will just return false. Note that switching literal positions for compareTo and
+ compareToIgnoreCase may change the result, see examples.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+class Foo {
+ boolean bar(String x) {
+ return x.equals("2"); // should be "2".equals(x)
+ }
+ boolean bar(String x) {
+ return x.equalsIgnoreCase("2"); // should be "2".equalsIgnoreCase(x)
+ }
+ boolean bar(String x) {
+ return (x.compareTo("bar") > 0); // should be: "bar".compareTo(x) < 0
+ }
+ boolean bar(String x) {
+ return (x.compareToIgnoreCase("bar") > 0); // should be: "bar".compareToIgnoreCase(x) < 0
+ }
+ boolean bar(String x) {
+ return x.contentEquals("bar"); // should be "bar".contentEquals(x)
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="LooseCoupling"
+ language="java"
+ since="0.7"
+ message="Avoid using implementation types like ''{0}''; use the interface instead"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.LooseCouplingRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#loosecoupling">
+ <description>
+ The use of implementation types (i.e., HashSet) as object references limits your ability to use alternate
+ implementations in the future as requirements change. Whenever available, referencing objects
+ by their interface types (i.e, Set) provides much more flexibility.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+import java.util.ArrayList;
+import java.util.HashSet;
+public class Bar {
+ // sub-optimal approach
+ private ArrayList<SomeType> list = new ArrayList<>();
+ public HashSet<SomeType> getFoo() {
+ return new HashSet<SomeType>();
+ }
+ // preferred approach
+ private List<SomeType> list = new ArrayList<>();
+ public Set<SomeType> getFoo() {
+ return new HashSet<SomeType>();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="MethodReturnsInternalArray"
+ language="java"
+ since="2.2"
+ message="Returning ''{0}'' may expose an internal array."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.MethodReturnsInternalArrayRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#methodreturnsinternalarray">
+ <description>
+ Exposing internal arrays to the caller violates object encapsulation since elements can be
+ removed or replaced outside of the object that owns it. It is safer to return a copy of the array.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class SecureSystem {
+ UserData [] ud;
+ public UserData [] getUserData() {
+ // Don't return directly the internal array, return a copy
+ return ud;
+ }
+}
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="MissingOverride"
+ language="java"
+ since="6.2.0"
+ minimumLanguageVersion="1.5"
+ message="The method ''{0}'' is missing an @Override annotation."
+ typeResolution="true"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.MissingOverrideRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#missingoverride">
+ <description>
+ Annotating overridden methods with @Override ensures at compile time that
+ the method really overrides one, which helps refactoring and clarifies intent.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+ public class Foo implements Runnable {
+ // This method is overridden, and should have an @Override annotation
+ public void run() {
+ }
+ }
+ ]]>
+ </example>
+ </rule>
+
+ <rule name="OneDeclarationPerLine"
+ language="java"
+ since="5.0"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ message="Use one line for each declaration, it enhances code readability."
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#onedeclarationperline">
+ <description>
+ Java allows the use of several variables declaration of the same type on one line. However, it
+ can lead to quite messy code. This rule looks for several declarations on the same line.
+ </description>
+ <priority>4</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//LocalVariableDeclaration
+ [not(parent::ForInit)]
+ [count(VariableDeclarator) > 1]
+ [$strictMode or count(distinct-values(VariableDeclarator/@BeginLine)) != count(VariableDeclarator)]
+|
+//FieldDeclaration
+ [count(VariableDeclarator) > 1]
+ [$strictMode or count(distinct-values(VariableDeclarator/@BeginLine)) != count(VariableDeclarator)]
+]]>
+ </value>
+ </property>
+ <property name="version" value="2.0"/>
+ <property name="strictMode" type="Boolean" value="false"
+ description="If true, mark combined declaration even if the declarations are on separate lines."/>
+ </properties>
+ <example>
+ <![CDATA[
+String name; // separate declarations
+String lastname;
+String name, lastname; // combined declaration, a violation
+String name,
+ lastname; // combined declaration on multiple lines, no violation by default.
+ // Set property strictMode to true to mark this as violation.
+]]>
+ </example>
+ </rule>
+
+ <rule name="PositionLiteralsFirstInCaseInsensitiveComparisons"
+ language="java"
+ since="5.1"
+ message="Position literals first in String comparisons for EqualsIgnoreCase"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.PositionLiteralsFirstInCaseInsensitiveComparisonsRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#positionliteralsfirstincaseinsensitivecomparisons"
+ deprecated="true">
+ <description>
+ Position literals first in comparisons, if the second argument is null then NullPointerExceptions
+ can be avoided, they will just return false.
+
+ This rule is replaced by the more general rule {% rule "LiteralsFirstInComparisons" %}.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+class Foo {
+ boolean bar(String x) {
+ return x.equalsIgnoreCase("2"); // should be "2".equalsIgnoreCase(x)
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="PositionLiteralsFirstInComparisons"
+ language="java"
+ since="3.3"
+ message="Position literals first in String comparisons"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.PositionLiteralsFirstInComparisonsRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#positionliteralsfirstincomparisons"
+ deprecated="true">
+ <description>
+ Position literals first in comparisons, if the second argument is null then NullPointerExceptions
+ can be avoided, they will just return false.
+
+ This rule is replaced by the more general rule {% rule "LiteralsFirstInComparisons" %}.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+class Foo {
+ boolean bar(String x) {
+ return x.equals("2"); // should be "2".equals(x)
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="PreserveStackTrace"
+ language="java"
+ since="3.7"
+ message="New exception is thrown in catch block, original stack trace may be lost"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.PreserveStackTraceRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#preservestacktrace">
+ <description>
+ Throwing a new exception from a catch block without passing the original exception into the
+ new exception will cause the original stack trace to be lost making it difficult to debug
+ effectively.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ void good() {
+ try{
+ Integer.parseInt("a");
+ } catch (Exception e) {
+ throw new Exception(e); // first possibility to create exception chain
+ }
+ try {
+ Integer.parseInt("a");
+ } catch (Exception e) {
+ throw (IllegalStateException)new IllegalStateException().initCause(e); // second possibility to create exception chain.
+ }
+ }
+ void bad() {
+ try{
+ Integer.parseInt("a");
+ } catch (Exception e) {
+ throw new Exception(e.getMessage());
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="PrimitiveWrapperInstantiation"
+ language="java"
+ since="6.37.0"
+ message="Do not use `new {0}(...)`, prefer `{0}.valueOf(...)`"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.PrimitiveWrapperInstantiationRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#primitivewrapperinstantiation">
+ <description>
+ Reports usages of primitive wrapper constructors. They are deprecated
+ since Java 9 and should not be used. Even before Java 9, they can
+ be replaced with usage of the corresponding static `valueOf` factory method
+ (which may be automatically inserted by the compiler since Java 1.5).
+ This has the advantage that it may reuse common instances instead of creating
+ a new instance each time.
+
+ Note that for `Boolean`, the named constants `Boolean.TRUE` and `Boolean.FALSE`
+ are preferred instead of `Boolean.valueOf`.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+ public class Foo {
+ private Integer ZERO = new Integer(0); // violation
+ private Integer ZERO1 = Integer.valueOf(0); // better
+ private Integer ZERO1 = 0; // even better
+ }
+ ]]>
+ </example>
+ </rule>
+
+
+ <rule name="ReplaceEnumerationWithIterator"
+ language="java"
+ since="3.4"
+ message="Consider replacing this Enumeration with the newer java.util.Iterator"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#replaceenumerationwithiterator">
+ <description>
+ Consider replacing Enumeration usages with the newer java.util.Iterator
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ImplementsList/ClassOrInterfaceType[@Image='Enumeration']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo implements Enumeration {
+ private int x = 42;
+ public boolean hasMoreElements() {
+ return true;
+ }
+ public Object nextElement() {
+ return String.valueOf(i++);
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ReplaceHashtableWithMap"
+ language="java"
+ since="3.4"
+ message="Consider replacing this Hashtable with the newer java.util.Map"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#replacehashtablewithmap">
+ <description>
+ Consider replacing Hashtable usage with the newer java.util.Map if thread safety is not required.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>//Type/ReferenceType/ClassOrInterfaceType[@Image='Hashtable']</value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo {
+ void bar() {
+ Hashtable h = new Hashtable();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ReplaceVectorWithList"
+ language="java"
+ since="3.4"
+ message="Consider replacing this Vector with the newer java.util.List"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#replacevectorwithlist">
+ <description>
+ Consider replacing Vector usages with the newer java.util.ArrayList if expensive thread-safe operations are not required.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>//Type/ReferenceType/ClassOrInterfaceType[@Image='Vector']</value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo {
+ void bar() {
+ Vector v = new Vector();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="SimplifiableTestAssertion"
+ language="java"
+ since="6.37.0"
+ message="Assertion may be simplified using {0}"
+ typeResolution="true"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.SimplifiableTestAssertionRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#simplifiabletestassertion">
+ <description>
+ Reports test assertions that may be simplified using a more specific
+ assertion method. This enables better error messages, and makes the
+ assertions more readable.
+
+ The rule only applies within test classes for the moment. It replaces
+ the deprecated rules {% rule UseAssertEqualsInsteadOfAssertTrue %},
+ {% rule UseAssertNullInsteadOfAssertTrue %}, {% rule UseAssertSameInsteadOfAssertTrue %},
+ {% rule UseAssertTrueInsteadOfAssertEquals %}, and {% rule java/design/SimplifyBooleanAssertion %}.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+import org.junit.Test;
+import static org.junit.Assert.*;
+class SomeTestClass {
+ Object a,b;
+ @Test
+ void testMethod() {
+ assertTrue(a.equals(b)); // could be assertEquals(a, b);
+ assertTrue(!a.equals(b)); // could be assertNotEquals(a, b);
+ assertTrue(!something); // could be assertFalse(something);
+ assertFalse(!something); // could be assertTrue(something);
+ assertTrue(a == b); // could be assertSame(a, b);
+ assertTrue(a != b); // could be assertNotSame(a, b);
+ assertTrue(a == null); // could be assertNull(a);
+ assertTrue(a != null); // could be assertNotNull(a);
+ }
+}
+ ]]>
+ </example>
+ </rule>
+
+ <rule name="SwitchStmtsShouldHaveDefault"
+ language="java"
+ since="1.0"
+ message="Switch statements should be exhaustive, add a default case (or missing enum branches)"
+ typeResolution="true"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#switchstmtsshouldhavedefault">
+ <description>
+ Switch statements should be exhaustive, to make their control flow
+ easier to follow. This can be achieved by adding a `default` case, or,
+ if the switch is on an enum type, by ensuring there is one switch branch
+ for each enum constant.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value><![CDATA[
+ //SwitchStatement[@DefaultCase = false() and @ExhaustiveEnumSwitch = false()]
+ ]]></value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+class Foo {{
+ int x = 2;
+ switch (x) {
+ case 1: int j = 6;
+ case 2: int j = 8;
+ // missing default: here
+ }
+}}
+]]>
+ </example>
+ </rule>
+
+ <rule name="SystemPrintln"
+ language="java"
+ since="2.1"
+ message="{0} is used"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#systemprintln">
+ <description>
+ References to System.(out|err).print are usually intended for debugging purposes and can remain in
+ the codebase even in production code. By using a logger one can enable/disable this behaviour at
+ will (and by priority) and avoid clogging the Standard out log.
+ </description>
+ <priority>2</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//Name[
+ starts-with(@Image, 'System.out.print')
+ or
+ starts-with(@Image, 'System.err.print')
+ ]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+class Foo{
+ Logger log = Logger.getLogger(Foo.class.getName());
+ public void testA () {
+ System.out.println("Entering test");
+ // Better use this
+ log.fine("Entering test");
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="UnusedAssignment"
+ language="java"
+ since="6.26.0"
+ message="The value assigned to this variable is never used or always overwritten"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.UnusedAssignmentRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#unusedassignment">
+ <description>
+ Reports assignments to variables that are never used before the variable is overwritten,
+ or goes out of scope. Unused assignments are those for which
+ 1. The variable is never read after the assignment, or
+ 2. The assigned value is always overwritten by other assignments before the next read of
+ the variable.
+
+ The rule doesn't consider assignments to fields except for those of `this` in a constructor,
+ or static fields of the current class in static initializers.
+
+ The rule may be suppressed with the standard `@SuppressWarnings("unused")` tag.
+
+ The rule subsumes {% rule "UnusedLocalVariable" %}, and {% rule "UnusedFormalParameter" %}.
+ Those violations are filtered
+ out by default, in case you already have enabled those rules, but may be enabled with the property
+ `reportUnusedVariables`. Variables whose name starts with `ignored` or `unused` are filtered out, as
+ is standard practice for exceptions.
+
+ Limitations:
+ * The rule currently cannot know which method calls throw exceptions, or which exceptions they throw.
+ In the body of a try block, every method or constructor call is assumed to throw. This may cause false-negatives.
+ The only other language construct that is assumed to throw is the `throw` statement, in particular,
+ things like `assert` statements, or NullPointerExceptions on dereference are ignored.
+ * The rule cannot resolve assignments across constructors, when they're called with the special
+ `this(...)` syntax. This may cause false-negatives.
+
+ Both of those limitations may be partly relaxed in PMD 7.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+ class A {
+ // this field initializer is redundant,
+ // it is always overwritten in the constructor
+ int f = 1;
+ A(int f) {
+ this.f = f;
+ }
+ }
+ ]]>
+ </example>
+ <example><![CDATA[
+class B {
+ int method(int i, int j) {
+ // this initializer is redundant,
+ // it is overwritten in all branches of the `if`
+ int k = 0;
+ // Both the assignments to k are unused, because k is
+ // not read after the if/else
+ // This may hide a bug: the programmer probably wanted to return k
+ if (i < j)
+ k = i;
+ else
+ k = j;
+ return j;
+ }
+}
+ ]]>
+
+ </example>
+ <example><![CDATA[
+class C {
+ int method() {
+ int i = 0;
+ checkSomething(++i);
+ checkSomething(++i);
+ checkSomething(++i);
+ checkSomething(++i);
+ // That last increment is not reported unless
+ // the property `checkUnusedPrefixIncrement` is
+ // set to `true`
+ // Technically it could be written (i+1), but it
+ // is not very important
+ }
+}
+ ]]>
+
+ </example>
+ <example><![CDATA[
+class C {
+ // variables that are truly unused (at most assigned to, but never accessed)
+ // are only reported if property `reportUnusedVariables` is true
+ void method(int param) { } // for example this method parameter
+ // even then, you can suppress the violation with an annotation:
+ void method(@SuppressWarning("unused") int param) { } // no violation, even if `reportUnusedVariables` is true
+ // For catch parameters, or for resources which don't need to be used explicitly,
+ // you can give a name that starts with "ignored" to ignore such warnings
+ {
+ try (Something ignored = Something.create()) {
+ // even if ignored is unused, it won't be flagged
+ // its purpose might be to side-effect in the create/close routines
+ } catch (Exception e) { // this is unused and will cause a warning if `reportUnusedVariables` is true
+ // you should choose a name that starts with "ignored"
+ return;
+ }
+ }
+}
+ ]]>
+
+ </example>
+ </rule>
+
+ <rule name="UnusedFormalParameter"
+ language="java"
+ since="0.8"
+ message="Avoid unused {0} parameters such as ''{1}''."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.UnusedFormalParameterRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#unusedformalparameter">
+ <description>
+ Reports parameters of methods and constructors that are not referenced them in the method body.
+ Parameters whose name starts with `ignored` or `unused` are filtered out.
+
+ Removing unused formal parameters from public methods could cause a ripple effect through the code base.
+ Hence, by default, this rule only considers private methods. To include non-private methods, set the
+ `checkAll` property to `true`.
+
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ private void bar(String howdy) {
+ // howdy is not used
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="UnusedImports"
+ language="java"
+ since="1.0"
+ message="Unused import ''{0}''"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.UnusedImportsRule"
+ typeResolution="true"
+ deprecated="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#unusedimports">
+ <description>
+ Reports import statements that are not used within the file. This also reports
+ duplicate imports, and imports from the same package. The simplest fix is just
+ to delete those imports.
+
+ This rule is deprecated since PMD 6.34.0. Use the rule {% rule "java/codestyle/UnnecessaryImport" %}
+ from category codestyle instead.
+ </description>
+ <priority>4</priority>
+ <example>
+ <![CDATA[
+import java.io.File; // not referenced or required
+import java.util.*; // not referenced or required
+public class Foo {}
+]]>
+ </example>
+ </rule>
+
+ <rule name="UnusedLocalVariable"
+ language="java"
+ since="0.1"
+ message="Avoid unused local variables such as ''{0}''."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.UnusedLocalVariableRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#unusedlocalvariable">
+ <description>
+ Detects when a local variable is declared and/or assigned, but not used.
+ Variables whose name starts with `ignored` or `unused` are filtered out.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ public void doSomething() {
+ int i = 5; // Unused
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="UnusedPrivateField"
Review comment:
This rule is enabled in our repo
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[GitHub] [ignite-3] alievmirza commented on a change in pull request #327: review pmd check rules
Posted by 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="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#brokennullcheck">
+ <description>
+ The null check is broken since it will throw a NullPointerException itself.
+ It is likely that you used || instead of && or vice versa.
+ </description>
+ <priority>2</priority>
+ <example>
+ <![CDATA[
+public String bar(String string) {
+ // should be &&
+ if (string!=null || !string.equals(""))
+ return string;
+ // should be ||
+ if (string==null && string.equals(""))
+ return string;
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="CallSuperFirst"
+ since="4.2.5"
+ language="java"
+ message="super should be called at the start of the method"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${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="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+ <description><
+ to have unintuitive behavior: NaN is considered unequal to itself.
+ This means a check like `someDouble == Double.NaN` will always return
+ false, even if `someDouble` is really the NaN value. To test whether a
+ value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+ (or `Float.isNaN`). The `!=` operator should be treated similarly.
+ Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+ and will always evaluate to false.
+
+ This rule has been renamed from "BadComparison" with PMD 6.36.0.
+ ]]></description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="ConstructorCallsOverridableMethod"
+ language="java"
+ since="1.04"
+ message="Overridable {0} called during object construction"
+ class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+ externalInfoUrl="${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 && 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="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+ <description><
+ to have unintuitive behavior: NaN is considered unequal to itself.
+ This means a check like `someDouble == Double.NaN` will always return
+ false, even if `someDouble` is really the NaN value. To test whether a
+ value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+ (or `Float.isNaN`). The `!=` operator should be treated similarly.
+ Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+ and will always evaluate to false.
+
+ This rule has been renamed from "BadComparison" with PMD 6.36.0.
+ ]]></description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="ConstructorCallsOverridableMethod"
+ language="java"
+ since="1.04"
+ message="Overridable {0} called during object construction"
+ class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+ externalInfoUrl="${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="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#brokennullcheck">
+ <description>
+ The null check is broken since it will throw a NullPointerException itself.
+ It is likely that you used || instead of && or vice versa.
+ </description>
+ <priority>2</priority>
+ <example>
+ <![CDATA[
+public String bar(String string) {
+ // should be &&
+ if (string!=null || !string.equals(""))
+ return string;
+ // should be ||
+ if (string==null && string.equals(""))
+ return string;
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="CallSuperFirst"
+ since="4.2.5"
+ language="java"
+ message="super should be called at the start of the method"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${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="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+ <description><
+ to have unintuitive behavior: NaN is considered unequal to itself.
+ This means a check like `someDouble == Double.NaN` will always return
+ false, even if `someDouble` is really the NaN value. To test whether a
+ value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+ (or `Float.isNaN`). The `!=` operator should be treated similarly.
+ Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+ and will always evaluate to false.
+
+ This rule has been renamed from "BadComparison" with PMD 6.36.0.
+ ]]></description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="ConstructorCallsOverridableMethod"
+ language="java"
+ since="1.04"
+ message="Overridable {0} called during object construction"
+ class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+ externalInfoUrl="${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 && 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="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+ <description><
+ to have unintuitive behavior: NaN is considered unequal to itself.
+ This means a check like `someDouble == Double.NaN` will always return
+ false, even if `someDouble` is really the NaN value. To test whether a
+ value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+ (or `Float.isNaN`). The `!=` operator should be treated similarly.
+ Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+ and will always evaluate to false.
+
+ This rule has been renamed from "BadComparison" with PMD 6.36.0.
+ ]]></description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="ConstructorCallsOverridableMethod"
+ language="java"
+ since="1.04"
+ message="Overridable {0} called during object construction"
+ class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+ externalInfoUrl="${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 && 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="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#comparisonwithnan">
+ <description><
+ to have unintuitive behavior: NaN is considered unequal to itself.
+ This means a check like `someDouble == Double.NaN` will always return
+ false, even if `someDouble` is really the NaN value. To test whether a
+ value is the NaN value, one should instead use `Double.isNaN(someDouble)`
+ (or `Float.isNaN`). The `!=` operator should be treated similarly.
+ Finally, comparisons like `someDouble <= Double.NaN` are nonsensical
+ and will always evaluate to false.
+
+ This rule has been renamed from "BadComparison" with PMD 6.36.0.
+ ]]></description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+(//EqualityExpression | //RelationalExpression)/PrimaryExpression/PrimaryPrefix/Name[@Image='Double.NaN' or @Image='Float.NaN']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+boolean x = (y == Double.NaN);
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="ConstructorCallsOverridableMethod"
+ language="java"
+ since="1.04"
+ message="Overridable {0} called during object construction"
+ class="net.sourceforge.pmd.lang.java.rule.errorprone.ConstructorCallsOverridableMethodRule"
+ externalInfoUrl="${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="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#useequalstocomparestrings">
+ <description>
+ Using '==' or '!=' to compare strings only works if intern version is used on both sides.
+ Use the equals() method instead.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//EqualityExpression
+ [count(PrimaryExpression[pmd-java:typeIs('java.lang.String')]) = 2]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public boolean test(String s) {
+ if (s == "one") return true; // unreliable
+ if ("two".equals(s)) return true; // better
+ return false;
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="UselessOperationOnImmutable"
Review comment:
This rule is enabled in our repo
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[GitHub] [ignite-3] alievmirza commented on a change in pull request #327: review pmd check rules
Posted by GitBox <gi...@apache.org>.
alievmirza commented on a change in pull request #327:
URL: https://github.com/apache/ignite-3/pull/327#discussion_r705398714
##########
File path: check-rules/bestpractices.xml
##########
@@ -0,0 +1,2130 @@
+<?xml version="1.0"?>
+
+<ruleset name="Best Practices"
+ xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+ xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+ <description>
+ Rules which enforce generally accepted best practices.
+ </description>
+
+ <rule name="AbstractClassWithoutAbstractMethod"
+ language="java"
+ since="3.0"
+ message="This abstract class does not have any abstract methods"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AbstractClassWithoutAbstractMethodRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#abstractclasswithoutabstractmethod">
+ <description>
+ The abstract class does not contain any abstract methods. An abstract class suggests
+ an incomplete implementation, which is to be completed by subclasses implementing the
+ abstract methods. If the class is intended to be used as a base class only (not to be instantiated
+ directly) a protected constructor can be provided prevent direct instantiation.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public abstract class Foo {
+ void int method1() { ... }
+ void int method2() { ... }
+ // consider using abstract methods or removing
+ // the abstract modifier and adding protected constructors
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AccessorClassGeneration"
+ language="java"
+ since="1.04"
+ maximumLanguageVersion="10"
+ message="Avoid instantiation through private constructors from outside of the constructor's class."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AccessorClassGenerationRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#accessorclassgeneration">
+ <description>
+ Instantiation by way of private constructors from outside of the constructor's class often causes the
+ generation of an accessor. A factory method, or non-privatization of the constructor can eliminate this
+ situation. The generated class file is actually an interface. It gives the accessing class the ability
+ to invoke a new hidden package scope constructor that takes the interface as a supplementary parameter.
+ This turns a private constructor effectively into one with package scope, and is challenging to discern.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Outer {
+ void method(){
+ Inner ic = new Inner();//Causes generation of accessor class
+ }
+ public class Inner {
+ private Inner(){}
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AccessorMethodGeneration"
+ language="java"
+ since="5.5.4"
+ maximumLanguageVersion="10"
+ message="Avoid autogenerated methods to access private fields and methods of inner / outer classes"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AccessorMethodGenerationRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#accessormethodgeneration">
+ <description>
+ When accessing private fields / methods from another class, the Java compiler will generate accessor methods
+ with package-private visibility. This adds overhead, and to the dex method count on Android. This situation can
+ be avoided by changing the visibility of the field / method from private to package-private.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class OuterClass {
+ private int counter;
+ /* package */ int id;
+ public class InnerClass {
+ InnerClass() {
+ OuterClass.this.counter++; // wrong accessor method will be generated
+ }
+ public int getOuterClassId() {
+ return OuterClass.this.id; // id is package-private, no accessor method needed
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ArrayIsStoredDirectly"
+ language="java"
+ since="2.2"
+ message="The user-supplied array ''{0}'' is stored directly."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.ArrayIsStoredDirectlyRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#arrayisstoreddirectly">
+ <description>
+ Constructors and methods receiving arrays should clone objects and store the copy.
+ This prevents future changes from the user from affecting the original array.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ private String [] x;
+ public void foo (String [] param) {
+ // Don't do this, make a copy of the array at least
+ this.x=param;
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidMessageDigestField"
+ language="java"
+ since="6.18.0"
+ message="You shouldn't declare field of MessageDigest type, because unsynchronized access could cause problems"
+ typeResolution="true"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidmessagedigestfield">
+ <description>
+ Declaring a MessageDigest instance as a field make this instance directly available to multiple threads.
+ Such sharing of MessageDigest instances should be avoided if possible since it leads to wrong results
+ if the access is not synchronized correctly.
+ Just create a new instance and use it locally, where you need it.
+ Creating a new instance is easier than synchronizing access to a shared instance.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//FieldDeclaration[pmd-java:typeIs('java.security.MessageDigest')]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+import java.security.MessageDigest;
+public class AvoidMessageDigestFieldExample {
+ private final MessageDigest sharedMd;
+ public AvoidMessageDigestFieldExample() throws Exception {
+ sharedMd = MessageDigest.getInstance("SHA-256");
+ }
+ public byte[] calculateHashShared(byte[] data) {
+ // sharing a MessageDigest like this without synchronizing access
+ // might lead to wrong results
+ sharedMd.reset();
+ sharedMd.update(data);
+ return sharedMd.digest();
+ }
+ // better
+ public byte[] calculateHash(byte[] data) throws Exception {
+ MessageDigest md = MessageDigest.getInstance("SHA-256");
+ md.update(data);
+ return md.digest();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidPrintStackTrace"
+ language="java"
+ since="3.2"
+ message="Avoid printStackTrace(); use a logger call instead."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidprintstacktrace">
+ <description>
+ Avoid printStackTrace(); use a logger call instead.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//PrimaryExpression[
+ ( PrimaryPrefix[Name[contains(@Image,'printStackTrace')]]
+ | PrimarySuffix[@Image='printStackTrace']
+ )/following-sibling::*[1][self::PrimarySuffix/Arguments[@Size=0]]
+]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+class Foo {
+ void bar() {
+ try {
+ // do something
+ } catch (Exception e) {
+ e.printStackTrace();
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidReassigningCatchVariables"
+ language="java"
+ since="6.27.0"
+ message="Avoid reassigning caught exception ''{0}''"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AvoidReassigningCatchVariablesRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidreassigningcatchvariables">
+ <description>
+ Reassigning exception variables caught in a catch statement should be avoided because of:
+
+ 1) If it is needed, multi catch can be easily added and code will still compile.
+
+ 2) Following the principle of least surprise we want to make sure that a variable caught in a catch statement
+ is always the one thrown in a try block.
+ </description>
+ <priority>3</priority>
+ <example><![CDATA[
+public class Foo {
+ public void foo() {
+ try {
+ // do something
+ } catch (Exception e) {
+ e = new NullPointerException(); // not recommended
+ }
+ try {
+ // do something
+ } catch (MyException | ServerException e) {
+ e = new RuntimeException(); // won't compile
+ }
+ }
+}
+ ]]></example>
+ </rule>
+
+ <rule name="AvoidReassigningLoopVariables"
+ language="java"
+ since="6.11.0"
+ message="Avoid reassigning the loop control variable ''{0}''"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AvoidReassigningLoopVariablesRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidreassigningloopvariables">
+ <description>
+ Reassigning loop variables can lead to hard-to-find bugs. Prevent or limit how these variables can be changed.
+
+ In foreach-loops, configured by the `foreachReassign` property:
+ - `deny`: Report any reassignment of the loop variable in the loop body. _This is the default._
+ - `allow`: Don't check the loop variable.
+ - `firstOnly`: Report any reassignments of the loop variable, except as the first statement in the loop body.
+ _This is useful if some kind of normalization or clean-up of the value before using is permitted, but any other change of the variable is not._
+
+ In for-loops, configured by the `forReassign` property:
+ - `deny`: Report any reassignment of the control variable in the loop body. _This is the default._
+ - `allow`: Don't check the control variable.
+ - `skip`: Report any reassignments of the control variable, except conditional increments/decrements (`++`, `--`, `+=`, `-=`).
+ _This prevents accidental reassignments or unconditional increments of the control variable._
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ private void foo() {
+ for (String s : listOfStrings()) {
+ s = s.trim(); // OK, when foreachReassign is "firstOnly" or "allow"
+ doSomethingWith(s);
+ s = s.toUpper(); // OK, when foreachReassign is "allow"
+ doSomethingElseWith(s);
+ }
+ for (int i=0; i < 10; i++) {
+ if (check(i)) {
+ i++; // OK, when forReassign is "skip" or "allow"
+ }
+ i = 5; // OK, when forReassign is "allow"
+ doSomethingWith(i);
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidReassigningParameters"
+ language="java"
+ since="1.0"
+ message="Avoid reassigning parameters such as ''{0}''"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AvoidReassigningParametersRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidreassigningparameters">
+ <description>
+ Reassigning values to incoming parameters of a method or constructor is not recommended, as this can
+ make the code more difficult to understand. The code is often read with the assumption that parameter values
+ don't change and an assignment violates therefore the principle of least astonishment. This is especially a
+ problem if the parameter is documented e.g. in the method's javadoc and the new content differs from the original
+ documented content.
+
+ Use temporary local variables instead. This allows you to assign a new name, which makes the code better
+ understandable.
+
+ Note that this rule considers both methods and constructors. If there are multiple assignments for a formal
+ parameter, then only the first assignment is reported.
+ </description>
+ <priority>2</priority>
+ <example>
+ <![CDATA[
+public class Hello {
+ private void greet(String name) {
+ name = name.trim();
+ System.out.println("Hello " + name);
+ // preferred
+ String trimmedName = name.trim();
+ System.out.println("Hello " + trimmedName);
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidStringBufferField"
+ language="java"
+ since="4.2"
+ message="StringBuffers can grow quite a lot, and so may become a source of memory leak (if the owning class has a long life time)."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidstringbufferfield">
+ <description>
+ StringBuffers/StringBuilders can grow considerably, and so may become a source of memory leaks
+ if held within objects with long lifetimes.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//FieldDeclaration/Type/ReferenceType/ClassOrInterfaceType[@Image = 'StringBuffer' or @Image = 'StringBuilder']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo {
+ private StringBuffer buffer; // potential memory leak as an instance variable;
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="AvoidUsingHardCodedIP"
+ language="java"
+ since="4.1"
+ message="Do not hard code the IP address ${variableName}"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.AvoidUsingHardCodedIPRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#avoidusinghardcodedip">
+ <description>
+ Application with hard-coded IP addresses can become impossible to deploy in some cases.
+ Externalizing IP adresses is preferable.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ private String ip = "127.0.0.1"; // not recommended
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="CheckResultSet"
+ language="java"
+ since="4.1"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.CheckResultSetRule"
+ message="Always check the return of one of the navigation method (next,previous,first,last) of a ResultSet."
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#checkresultset">
+ <description>
+ Always check the return values of navigation methods (next, previous, first, last) of a ResultSet.
+ If the value return is 'false', it should be handled properly.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+Statement stat = conn.createStatement();
+ResultSet rst = stat.executeQuery("SELECT name FROM person");
+rst.next(); // what if it returns false? bad form
+String firstName = rst.getString(1);
+Statement stat = conn.createStatement();
+ResultSet rst = stat.executeQuery("SELECT name FROM person");
+if (rst.next()) { // result is properly examined and used
+ String firstName = rst.getString(1);
+ } else {
+ // handle missing data
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ConstantsInInterface"
+ language="java"
+ since="5.5"
+ message="Avoid constants in interfaces. Interfaces define types, constants are implementation details better placed in classes or enums. See Effective Java, item 19."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#constantsininterface">
+ <description>
+ Avoid constants in interfaces. Interfaces should define types, constants are implementation details
+ better placed in classes or enums. See Effective Java, item 19.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="ignoreIfHasMethods" type="Boolean" description="Whether to ignore constants in interfaces if the interface defines any methods" value="true"/>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceDeclaration[@Interface= true()][$ignoreIfHasMethods= false() or not(.//MethodDeclaration)]//FieldDeclaration
+ ]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public interface ConstantInterface {
+ public static final int CONST1 = 1; // violation, no fields allowed in interface!
+ static final int CONST2 = 1; // violation, no fields allowed in interface!
+ final int CONST3 = 1; // violation, no fields allowed in interface!
+ int CONST4 = 1; // violation, no fields allowed in interface!
+}
+// with ignoreIfHasMethods = false
+public interface AnotherConstantInterface {
+ public static final int CONST1 = 1; // violation, no fields allowed in interface!
+ int anyMethod();
+}
+// with ignoreIfHasMethods = true
+public interface YetAnotherConstantInterface {
+ public static final int CONST1 = 1; // no violation
+ int anyMethod();
+}
+ ]]>
+ </example>
+ </rule>
+
+ <rule name="DefaultLabelNotLastInSwitchStmt"
+ language="java"
+ since="1.5"
+ message="The default label should be the last label in a switch statement"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#defaultlabelnotlastinswitchstmt">
+ <description>
+ By convention, the default label should be the last label in a switch statement.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//SwitchStatement
+ [not(SwitchLabel[position() = last()][@Default= true()])]
+ [SwitchLabel[@Default= true()]]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo {
+ void bar(int a) {
+ switch (a) {
+ case 1: // do something
+ break;
+ default: // the default case should be last, by convention
+ break;
+ case 2:
+ break;
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="DoubleBraceInitialization"
+ language="java"
+ since="6.16.0"
+ message="Double-brace initialization should be avoided"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#doublebraceinitialization">
+ <description>
+ Double brace initialisation is a pattern to initialise eg collections concisely. But it implicitly
+ generates a new .class file, and the object holds a strong reference to the enclosing object. For those
+ reasons, it is preferable to initialize the object normally, even though it's verbose.
+
+ This rule counts any anonymous class which only has a single initializer as an instance of double-brace
+ initialization. There is currently no way to find out whether a method called in the initializer is not
+ accessible from outside the anonymous class, and those legit cases should be suppressed for the time being.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//AllocationExpression/ClassOrInterfaceBody[count(*)=1]/*/Initializer[@Static=false()]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example><![CDATA[
+// this is double-brace initialization
+return new ArrayList<String>(){{
+ add("a");
+ add("b");
+ add("c");
+}};
+// the better way is to not create an anonymous class:
+List<String> a = new ArrayList<>();
+a.add("a");
+a.add("b");
+a.add("c");
+return a;
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="ForLoopCanBeForeach"
+ language="java"
+ since="6.0.0"
+ message="This 'for' loop can be replaced by a 'foreach' loop"
+ typeResolution="true"
+ minimumLanguageVersion="1.5"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.ForLoopCanBeForeachRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#forloopcanbeforeach">
+ <description>
+ Reports loops that can be safely replaced with the foreach syntax. The rule considers loops over
+ lists, arrays and iterators. A loop is safe to replace if it only uses the index variable to
+ access an element of the list or array, only has one update statement, and loops through *every*
+ element of the list or array left to right.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class MyClass {
+ void loop(List<String> l) {
+ for (int i = 0; i < l.size(); i++) { // pre Java 1.5
+ System.out.println(l.get(i));
+ }
+ for (String s : l) { // post Java 1.5
+ System.out.println(s);
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ForLoopVariableCount"
+ language="java"
+ since="6.11.0"
+ message="Too many control variables in the 'for' statement"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#forloopvariablecount">
+ <description>
+ Having a lot of control variables in a 'for' loop makes it harder to see what range of values
+ the loop iterates over. By default this rule allows a regular 'for' loop with only one variable.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="maximumVariables" type="Integer"
+ description="A regular for statement will have 1 control variable" min="0" max="100" value="1"/>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>//ForInit/LocalVariableDeclaration[count(VariableDeclarator) > $maximumVariables]</value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+// this will be reported with the default setting of at most one control variable in a for loop
+for (int i = 0, j = 0; i < 10; i++, j += 2) {
+ foo();
+]]>
+ </example>
+ </rule>
+
+ <rule name="GuardLogStatement"
+ language="java"
+ since="5.1.0"
+ message="Logger calls should be surrounded by log level guards."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.GuardLogStatementRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#guardlogstatement">
+ <description>
+ Whenever using a log level, one should check if the loglevel is actually enabled, or
+ otherwise skip the associate String creation and manipulation.
+
+ An alternative to checking the log level are substituting parameters, formatters or lazy logging
+ with lambdas. The available alternatives depend on the actual logging framework.
+ </description>
+ <priority>2</priority>
+ <example>
+ <![CDATA[
+// Add this for performance
+if (log.isDebugEnabled()) {
+ log.debug("log something" + param1 + " and " + param2 + "concat strings");
+}
+// Avoid the guarding if statement with substituting parameters
+log.debug("log something {} and {}", param1, param2);
+// Avoid the guarding if statement with formatters
+log.debug("log something %s and %s", param1, param2);
+// Avoid the guarding if statement with lazy logging and lambdas
+log.debug("log something expensive: {}", () -> calculateExpensiveLoggingText());
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit4SuitesShouldUseSuiteAnnotation"
+ language="java"
+ since="4.0"
+ message="JUnit 4 indicates test suites via annotations, not the suite method."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit4suitesshouldusesuiteannotation">
+ <description>
+ In JUnit 3, test suites are indicated by the suite() method. In JUnit 4, suites are indicated
+ through the @RunWith(Suite.class) annotation.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceBodyDeclaration
+[MethodDeclaration[@Name='suite']/ResultType/Type/ReferenceType/ClassOrInterfaceType[pmd-java:typeIs('junit.framework.Test')]]
+[not(MethodDeclaration/Block/BlockStatement/Statement/ReturnStatement//ClassOrInterfaceType[pmd-java:typeIs('junit.framework.JUnit4TestAdapter')])]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class BadExample extends TestCase{
+ public static Test suite(){
+ return new Suite();
+ }
+}
+@RunWith(Suite.class)
+@SuiteClasses( { TestOne.class, TestTwo.class })
+public class GoodTest {
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit4TestShouldUseAfterAnnotation"
+ language="java"
+ since="4.0"
+ message="JUnit 4 tests that clean up tests should use the @After annotation, JUnit5 tests should use @AfterEach or @AfterAll"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit4testshoulduseafterannotation">
+ <description>
+ In JUnit 3, the tearDown method was used to clean up all data entities required in running tests.
+ JUnit 4 skips the tearDown method and executes all methods annotated with @After after running each test.
+ JUnit 5 introduced @AfterEach and @AfterAll annotations to execute methods after each test or after all tests in the class, respectively.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceBodyDeclaration
+ [MethodDeclaration[@Name='tearDown']]
+ [not(Annotation/*/Name[
+ pmd-java:typeIs('org.junit.After')
+ or pmd-java:typeIs('org.junit.jupiter.api.AfterEach')
+ or pmd-java:typeIs('org.junit.jupiter.api.AfterAll')
+ or pmd-java:typeIs('org.testng.annotations.AfterMethod')])]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class MyTest {
+ public void tearDown() {
+ bad();
+ }
+}
+public class MyTest2 {
+ @After public void tearDown() {
+ good();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit4TestShouldUseBeforeAnnotation"
+ language="java"
+ since="4.0"
+ message="JUnit 4 tests that set up tests should use the @Before annotation, JUnit5 tests should use @BeforeEach or @BeforeAll"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit4testshouldusebeforeannotation">
+ <description>
+ In JUnit 3, the setUp method was used to set up all data entities required in running tests.
+ JUnit 4 skips the setUp method and executes all methods annotated with @Before before all tests.
+ JUnit 5 introduced @BeforeEach and @BeforeAll annotations to execute methods before each test or before all tests in the class, respectively.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceBodyDeclaration
+ [MethodDeclaration[@Name='setUp']]
+ [not(Annotation/*/Name[
+ pmd-java:typeIs('org.junit.Before')
+ or pmd-java:typeIs('org.junit.jupiter.api.BeforeEach')
+ or pmd-java:typeIs('org.junit.jupiter.api.BeforeAll')
+ or pmd-java:typeIs('org.testng.annotations.BeforeMethod')])]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class MyTest {
+ public void setUp() {
+ bad();
+ }
+}
+public class MyTest2 {
+ @Before public void setUp() {
+ good();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit4TestShouldUseTestAnnotation"
+ language="java"
+ since="4.0"
+ message="JUnit 4 tests that execute tests should use the @Test annotation, JUnit 5 tests should use @Test, @RepeatedTest, @TestFactory, @TestTemplate or @ParameterizedTest"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit4testshouldusetestannotation">
+ <description>
+ In JUnit 3, the framework executed all methods which started with the word test as a unit test.
+ In JUnit 4, only methods annotated with the @Test annotation are executed.
+ In JUnit 5, one of the following annotations should be used for tests: @Test, @RepeatedTest, @TestFactory, @TestTemplate or @ParameterizedTest.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceDeclaration[
+ matches(@SimpleName, $testClassPattern)
+ or ExtendsList/ClassOrInterfaceType[pmd-java:typeIs('junit.framework.TestCase')]]
+ /ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration[MethodDeclaration[@Public=true() and starts-with(@Name, 'test')]]
+ [not(Annotation//Name[
+ pmd-java:typeIs('org.junit.Test')
+ or pmd-java:typeIs('org.junit.jupiter.api.Test') or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
+ or pmd-java:typeIs('org.junit.jupiter.api.TestFactory') or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
+ or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')
+ ])]
+]]>
+ </value>
+ </property>
+ <property name="testClassPattern" type="Regex" description="The regex pattern used to identify test classes" value="Test" />
+ <property name="version" value="2.0"/>
+ </properties>
+ <example>
+ <![CDATA[
+public class MyTest {
+ public void testBad() {
+ doSomething();
+ }
+ @Test
+ public void testGood() {
+ doSomething();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnit5TestShouldBePackagePrivate"
+ language="java"
+ since="6.35.0"
+ message="JUnit 5 tests should be package-private."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junit5testshouldbepackageprivate">
+ <description><![CDATA[
+Reports JUnit 5 test classes and methods that are not package-private.
+Contrary to JUnit 4 tests, which required public visibility to be run by the engine,
+JUnit 5 tests can also be run if they're package-private. Marking them as such
+is a good practice to limit their visibility.
+Test methods are identified as those which use `@Test`, `@RepeatedTest`,
+`@TestFactory`, `@TestTemplate` or `@ParameterizedTest`.
+ ]]></description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ClassOrInterfaceDeclaration[
+ (: a Junit 5 test class, ie, it has methods with the annotation :)
+ @Interface=false() and
+ ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration
+ [Annotation//Name[
+ 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')
+ ]]
+ [MethodDeclaration]
+]/(
+ self::*[@Abstract=false() and (@Public=true() or @Protected=true())]
+| ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration
+ [Annotation//Name[
+ 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')
+ ]]
+ /MethodDeclaration[@Public=true() or @Protected=true()]
+)
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+class MyTest { // not public, that's fine
+ @Test
+ public void testBad() { } // should not have a public modifier
+ @Test
+ protected void testAlsoBad() { } // should not have a protected modifier
+ @Test
+ private void testNoRun() { } // should not have a private modifier
+ @Test
+ void testGood() { } // package private as expected
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnitAssertionsShouldIncludeMessage"
+ language="java"
+ since="1.04"
+ message="JUnit assertions should include a message"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.JUnitAssertionsShouldIncludeMessageRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junitassertionsshouldincludemessage">
+ <description>
+ JUnit assertions should include an informative message - i.e., use the three-argument version of
+ assertEquals(), not the two-argument version.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo extends TestCase {
+ public void testSomething() {
+ assertEquals("foo", "bar");
+ // Use the form:
+ // assertEquals("Foo does not equals bar", "foo", "bar");
+ // instead
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnitTestContainsTooManyAsserts"
+ language="java"
+ since="5.0"
+ message="Unit tests should not contain more than ${maximumAsserts} assert(s)."
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junittestcontainstoomanyasserts">
+ <description>
+ Unit tests should not contain too many asserts. Many asserts are indicative of a complex test, for which
+ it is harder to verify correctness. Consider breaking the test scenario into multiple, shorter test scenarios.
+ Customize the maximum number of assertions used by this Rule to suit your needs.
+
+ This rule checks for JUnit4, JUnit5 and TestNG Tests, as well as methods starting with "test".
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="maximumAsserts" type="Integer" min="1" max="1000" description="Maximum number of Asserts in a test method" value="1"/>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//MethodDeclaration[@Name[matches(.,'^test')] or ../Annotation/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')
+ or pmd-java:typeIs('org.testng.annotations.Test')
+ ]]
+ [count(.//PrimaryPrefix/Name[@Image[matches(.,'^assert')]]) > $maximumAsserts]
+]]>
+ </value>
+ </property>
+ <property name="version" value="2.0"/>
+ </properties>
+ <example>
+ <![CDATA[
+public class MyTestCase extends TestCase {
+ // Ok
+ public void testMyCaseWithOneAssert() {
+ boolean myVar = false;
+ assertFalse("should be false", myVar);
+ }
+ // Bad, too many asserts (assuming max=1)
+ public void testMyCaseWithMoreAsserts() {
+ boolean myVar = false;
+ assertFalse("myVar should be false", myVar);
+ assertEquals("should equals false", false, myVar);
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnitTestsShouldIncludeAssert"
+ language="java"
+ since="2.0"
+ message="JUnit tests should include assert() or fail()"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.JUnitTestsShouldIncludeAssertRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junittestsshouldincludeassert">
+ <description>
+ JUnit tests should include at least one assertion. This makes the tests more robust, and using assert
+ with messages provide the developer a clearer idea of what the test does.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo extends TestCase {
+ public void testSomething() {
+ Bar b = findBar();
+ // This is better than having a NullPointerException
+ // assertNotNull("bar not found", b);
+ b.work();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="JUnitUseExpected"
+ language="java"
+ since="4.0"
+ message="In JUnit4, use the @Test(expected) annotation to denote tests that should throw exceptions"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.JUnitUseExpectedRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#junituseexpected">
+ <description>
+ In JUnit4, use the @Test(expected) annotation to denote tests that should throw exceptions.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class MyTest {
+ @Test
+ public void testBad() {
+ try {
+ doSomething();
+ fail("should have thrown an exception");
+ } catch (Exception e) {
+ }
+ }
+ @Test(expected=Exception.class)
+ public void testGood() {
+ doSomething();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="LiteralsFirstInComparisons"
+ language="java"
+ since="6.24.0"
+ message="Position literals first in String comparisons"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.LiteralsFirstInComparisonsRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#literalsfirstincomparisons">
+ <description>
+ Position literals first in all String comparisons, if the second argument is null then NullPointerExceptions
+ can be avoided, they will just return false. Note that switching literal positions for compareTo and
+ compareToIgnoreCase may change the result, see examples.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+class Foo {
+ boolean bar(String x) {
+ return x.equals("2"); // should be "2".equals(x)
+ }
+ boolean bar(String x) {
+ return x.equalsIgnoreCase("2"); // should be "2".equalsIgnoreCase(x)
+ }
+ boolean bar(String x) {
+ return (x.compareTo("bar") > 0); // should be: "bar".compareTo(x) < 0
+ }
+ boolean bar(String x) {
+ return (x.compareToIgnoreCase("bar") > 0); // should be: "bar".compareToIgnoreCase(x) < 0
+ }
+ boolean bar(String x) {
+ return x.contentEquals("bar"); // should be "bar".contentEquals(x)
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="LooseCoupling"
+ language="java"
+ since="0.7"
+ message="Avoid using implementation types like ''{0}''; use the interface instead"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.LooseCouplingRule"
+ typeResolution="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#loosecoupling">
+ <description>
+ The use of implementation types (i.e., HashSet) as object references limits your ability to use alternate
+ implementations in the future as requirements change. Whenever available, referencing objects
+ by their interface types (i.e, Set) provides much more flexibility.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+import java.util.ArrayList;
+import java.util.HashSet;
+public class Bar {
+ // sub-optimal approach
+ private ArrayList<SomeType> list = new ArrayList<>();
+ public HashSet<SomeType> getFoo() {
+ return new HashSet<SomeType>();
+ }
+ // preferred approach
+ private List<SomeType> list = new ArrayList<>();
+ public Set<SomeType> getFoo() {
+ return new HashSet<SomeType>();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="MethodReturnsInternalArray"
+ language="java"
+ since="2.2"
+ message="Returning ''{0}'' may expose an internal array."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.MethodReturnsInternalArrayRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#methodreturnsinternalarray">
+ <description>
+ Exposing internal arrays to the caller violates object encapsulation since elements can be
+ removed or replaced outside of the object that owns it. It is safer to return a copy of the array.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class SecureSystem {
+ UserData [] ud;
+ public UserData [] getUserData() {
+ // Don't return directly the internal array, return a copy
+ return ud;
+ }
+}
+]]>
+ </example>
+ </rule>
+
+
+ <rule name="MissingOverride"
+ language="java"
+ since="6.2.0"
+ minimumLanguageVersion="1.5"
+ message="The method ''{0}'' is missing an @Override annotation."
+ typeResolution="true"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.MissingOverrideRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#missingoverride">
+ <description>
+ Annotating overridden methods with @Override ensures at compile time that
+ the method really overrides one, which helps refactoring and clarifies intent.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+ public class Foo implements Runnable {
+ // This method is overridden, and should have an @Override annotation
+ public void run() {
+ }
+ }
+ ]]>
+ </example>
+ </rule>
+
+ <rule name="OneDeclarationPerLine"
+ language="java"
+ since="5.0"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ message="Use one line for each declaration, it enhances code readability."
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#onedeclarationperline">
+ <description>
+ Java allows the use of several variables declaration of the same type on one line. However, it
+ can lead to quite messy code. This rule looks for several declarations on the same line.
+ </description>
+ <priority>4</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//LocalVariableDeclaration
+ [not(parent::ForInit)]
+ [count(VariableDeclarator) > 1]
+ [$strictMode or count(distinct-values(VariableDeclarator/@BeginLine)) != count(VariableDeclarator)]
+|
+//FieldDeclaration
+ [count(VariableDeclarator) > 1]
+ [$strictMode or count(distinct-values(VariableDeclarator/@BeginLine)) != count(VariableDeclarator)]
+]]>
+ </value>
+ </property>
+ <property name="version" value="2.0"/>
+ <property name="strictMode" type="Boolean" value="false"
+ description="If true, mark combined declaration even if the declarations are on separate lines."/>
+ </properties>
+ <example>
+ <![CDATA[
+String name; // separate declarations
+String lastname;
+String name, lastname; // combined declaration, a violation
+String name,
+ lastname; // combined declaration on multiple lines, no violation by default.
+ // Set property strictMode to true to mark this as violation.
+]]>
+ </example>
+ </rule>
+
+ <rule name="PositionLiteralsFirstInCaseInsensitiveComparisons"
+ language="java"
+ since="5.1"
+ message="Position literals first in String comparisons for EqualsIgnoreCase"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.PositionLiteralsFirstInCaseInsensitiveComparisonsRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#positionliteralsfirstincaseinsensitivecomparisons"
+ deprecated="true">
+ <description>
+ Position literals first in comparisons, if the second argument is null then NullPointerExceptions
+ can be avoided, they will just return false.
+
+ This rule is replaced by the more general rule {% rule "LiteralsFirstInComparisons" %}.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+class Foo {
+ boolean bar(String x) {
+ return x.equalsIgnoreCase("2"); // should be "2".equalsIgnoreCase(x)
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="PositionLiteralsFirstInComparisons"
+ language="java"
+ since="3.3"
+ message="Position literals first in String comparisons"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.PositionLiteralsFirstInComparisonsRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#positionliteralsfirstincomparisons"
+ deprecated="true">
+ <description>
+ Position literals first in comparisons, if the second argument is null then NullPointerExceptions
+ can be avoided, they will just return false.
+
+ This rule is replaced by the more general rule {% rule "LiteralsFirstInComparisons" %}.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+class Foo {
+ boolean bar(String x) {
+ return x.equals("2"); // should be "2".equals(x)
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="PreserveStackTrace"
+ language="java"
+ since="3.7"
+ message="New exception is thrown in catch block, original stack trace may be lost"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.PreserveStackTraceRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#preservestacktrace">
+ <description>
+ Throwing a new exception from a catch block without passing the original exception into the
+ new exception will cause the original stack trace to be lost making it difficult to debug
+ effectively.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ void good() {
+ try{
+ Integer.parseInt("a");
+ } catch (Exception e) {
+ throw new Exception(e); // first possibility to create exception chain
+ }
+ try {
+ Integer.parseInt("a");
+ } catch (Exception e) {
+ throw (IllegalStateException)new IllegalStateException().initCause(e); // second possibility to create exception chain.
+ }
+ }
+ void bad() {
+ try{
+ Integer.parseInt("a");
+ } catch (Exception e) {
+ throw new Exception(e.getMessage());
+ }
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="PrimitiveWrapperInstantiation"
+ language="java"
+ since="6.37.0"
+ message="Do not use `new {0}(...)`, prefer `{0}.valueOf(...)`"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.PrimitiveWrapperInstantiationRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#primitivewrapperinstantiation">
+ <description>
+ Reports usages of primitive wrapper constructors. They are deprecated
+ since Java 9 and should not be used. Even before Java 9, they can
+ be replaced with usage of the corresponding static `valueOf` factory method
+ (which may be automatically inserted by the compiler since Java 1.5).
+ This has the advantage that it may reuse common instances instead of creating
+ a new instance each time.
+
+ Note that for `Boolean`, the named constants `Boolean.TRUE` and `Boolean.FALSE`
+ are preferred instead of `Boolean.valueOf`.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+ public class Foo {
+ private Integer ZERO = new Integer(0); // violation
+ private Integer ZERO1 = Integer.valueOf(0); // better
+ private Integer ZERO1 = 0; // even better
+ }
+ ]]>
+ </example>
+ </rule>
+
+
+ <rule name="ReplaceEnumerationWithIterator"
+ language="java"
+ since="3.4"
+ message="Consider replacing this Enumeration with the newer java.util.Iterator"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#replaceenumerationwithiterator">
+ <description>
+ Consider replacing Enumeration usages with the newer java.util.Iterator
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//ImplementsList/ClassOrInterfaceType[@Image='Enumeration']
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo implements Enumeration {
+ private int x = 42;
+ public boolean hasMoreElements() {
+ return true;
+ }
+ public Object nextElement() {
+ return String.valueOf(i++);
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ReplaceHashtableWithMap"
+ language="java"
+ since="3.4"
+ message="Consider replacing this Hashtable with the newer java.util.Map"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#replacehashtablewithmap">
+ <description>
+ Consider replacing Hashtable usage with the newer java.util.Map if thread safety is not required.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>//Type/ReferenceType/ClassOrInterfaceType[@Image='Hashtable']</value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo {
+ void bar() {
+ Hashtable h = new Hashtable();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="ReplaceVectorWithList"
+ language="java"
+ since="3.4"
+ message="Consider replacing this Vector with the newer java.util.List"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#replacevectorwithlist">
+ <description>
+ Consider replacing Vector usages with the newer java.util.ArrayList if expensive thread-safe operations are not required.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>//Type/ReferenceType/ClassOrInterfaceType[@Image='Vector']</value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+public class Foo {
+ void bar() {
+ Vector v = new Vector();
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="SimplifiableTestAssertion"
+ language="java"
+ since="6.37.0"
+ message="Assertion may be simplified using {0}"
+ typeResolution="true"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.SimplifiableTestAssertionRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#simplifiabletestassertion">
+ <description>
+ Reports test assertions that may be simplified using a more specific
+ assertion method. This enables better error messages, and makes the
+ assertions more readable.
+
+ The rule only applies within test classes for the moment. It replaces
+ the deprecated rules {% rule UseAssertEqualsInsteadOfAssertTrue %},
+ {% rule UseAssertNullInsteadOfAssertTrue %}, {% rule UseAssertSameInsteadOfAssertTrue %},
+ {% rule UseAssertTrueInsteadOfAssertEquals %}, and {% rule java/design/SimplifyBooleanAssertion %}.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+import org.junit.Test;
+import static org.junit.Assert.*;
+class SomeTestClass {
+ Object a,b;
+ @Test
+ void testMethod() {
+ assertTrue(a.equals(b)); // could be assertEquals(a, b);
+ assertTrue(!a.equals(b)); // could be assertNotEquals(a, b);
+ assertTrue(!something); // could be assertFalse(something);
+ assertFalse(!something); // could be assertTrue(something);
+ assertTrue(a == b); // could be assertSame(a, b);
+ assertTrue(a != b); // could be assertNotSame(a, b);
+ assertTrue(a == null); // could be assertNull(a);
+ assertTrue(a != null); // could be assertNotNull(a);
+ }
+}
+ ]]>
+ </example>
+ </rule>
+
+ <rule name="SwitchStmtsShouldHaveDefault"
+ language="java"
+ since="1.0"
+ message="Switch statements should be exhaustive, add a default case (or missing enum branches)"
+ typeResolution="true"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#switchstmtsshouldhavedefault">
+ <description>
+ Switch statements should be exhaustive, to make their control flow
+ easier to follow. This can be achieved by adding a `default` case, or,
+ if the switch is on an enum type, by ensuring there is one switch branch
+ for each enum constant.
+ </description>
+ <priority>3</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value><![CDATA[
+ //SwitchStatement[@DefaultCase = false() and @ExhaustiveEnumSwitch = false()]
+ ]]></value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+class Foo {{
+ int x = 2;
+ switch (x) {
+ case 1: int j = 6;
+ case 2: int j = 8;
+ // missing default: here
+ }
+}}
+]]>
+ </example>
+ </rule>
+
+ <rule name="SystemPrintln"
+ language="java"
+ since="2.1"
+ message="{0} is used"
+ class="net.sourceforge.pmd.lang.rule.XPathRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#systemprintln">
+ <description>
+ References to System.(out|err).print are usually intended for debugging purposes and can remain in
+ the codebase even in production code. By using a logger one can enable/disable this behaviour at
+ will (and by priority) and avoid clogging the Standard out log.
+ </description>
+ <priority>2</priority>
+ <properties>
+ <property name="version" value="2.0"/>
+ <property name="xpath">
+ <value>
+ <![CDATA[
+//Name[
+ starts-with(@Image, 'System.out.print')
+ or
+ starts-with(@Image, 'System.err.print')
+ ]
+]]>
+ </value>
+ </property>
+ </properties>
+ <example>
+ <![CDATA[
+class Foo{
+ Logger log = Logger.getLogger(Foo.class.getName());
+ public void testA () {
+ System.out.println("Entering test");
+ // Better use this
+ log.fine("Entering test");
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="UnusedAssignment"
+ language="java"
+ since="6.26.0"
+ message="The value assigned to this variable is never used or always overwritten"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.UnusedAssignmentRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#unusedassignment">
+ <description>
+ Reports assignments to variables that are never used before the variable is overwritten,
+ or goes out of scope. Unused assignments are those for which
+ 1. The variable is never read after the assignment, or
+ 2. The assigned value is always overwritten by other assignments before the next read of
+ the variable.
+
+ The rule doesn't consider assignments to fields except for those of `this` in a constructor,
+ or static fields of the current class in static initializers.
+
+ The rule may be suppressed with the standard `@SuppressWarnings("unused")` tag.
+
+ The rule subsumes {% rule "UnusedLocalVariable" %}, and {% rule "UnusedFormalParameter" %}.
+ Those violations are filtered
+ out by default, in case you already have enabled those rules, but may be enabled with the property
+ `reportUnusedVariables`. Variables whose name starts with `ignored` or `unused` are filtered out, as
+ is standard practice for exceptions.
+
+ Limitations:
+ * The rule currently cannot know which method calls throw exceptions, or which exceptions they throw.
+ In the body of a try block, every method or constructor call is assumed to throw. This may cause false-negatives.
+ The only other language construct that is assumed to throw is the `throw` statement, in particular,
+ things like `assert` statements, or NullPointerExceptions on dereference are ignored.
+ * The rule cannot resolve assignments across constructors, when they're called with the special
+ `this(...)` syntax. This may cause false-negatives.
+
+ Both of those limitations may be partly relaxed in PMD 7.
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+ class A {
+ // this field initializer is redundant,
+ // it is always overwritten in the constructor
+ int f = 1;
+ A(int f) {
+ this.f = f;
+ }
+ }
+ ]]>
+ </example>
+ <example><![CDATA[
+class B {
+ int method(int i, int j) {
+ // this initializer is redundant,
+ // it is overwritten in all branches of the `if`
+ int k = 0;
+ // Both the assignments to k are unused, because k is
+ // not read after the if/else
+ // This may hide a bug: the programmer probably wanted to return k
+ if (i < j)
+ k = i;
+ else
+ k = j;
+ return j;
+ }
+}
+ ]]>
+
+ </example>
+ <example><![CDATA[
+class C {
+ int method() {
+ int i = 0;
+ checkSomething(++i);
+ checkSomething(++i);
+ checkSomething(++i);
+ checkSomething(++i);
+ // That last increment is not reported unless
+ // the property `checkUnusedPrefixIncrement` is
+ // set to `true`
+ // Technically it could be written (i+1), but it
+ // is not very important
+ }
+}
+ ]]>
+
+ </example>
+ <example><![CDATA[
+class C {
+ // variables that are truly unused (at most assigned to, but never accessed)
+ // are only reported if property `reportUnusedVariables` is true
+ void method(int param) { } // for example this method parameter
+ // even then, you can suppress the violation with an annotation:
+ void method(@SuppressWarning("unused") int param) { } // no violation, even if `reportUnusedVariables` is true
+ // For catch parameters, or for resources which don't need to be used explicitly,
+ // you can give a name that starts with "ignored" to ignore such warnings
+ {
+ try (Something ignored = Something.create()) {
+ // even if ignored is unused, it won't be flagged
+ // its purpose might be to side-effect in the create/close routines
+ } catch (Exception e) { // this is unused and will cause a warning if `reportUnusedVariables` is true
+ // you should choose a name that starts with "ignored"
+ return;
+ }
+ }
+}
+ ]]>
+
+ </example>
+ </rule>
+
+ <rule name="UnusedFormalParameter"
+ language="java"
+ since="0.8"
+ message="Avoid unused {0} parameters such as ''{1}''."
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.UnusedFormalParameterRule"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#unusedformalparameter">
+ <description>
+ Reports parameters of methods and constructors that are not referenced them in the method body.
+ Parameters whose name starts with `ignored` or `unused` are filtered out.
+
+ Removing unused formal parameters from public methods could cause a ripple effect through the code base.
+ Hence, by default, this rule only considers private methods. To include non-private methods, set the
+ `checkAll` property to `true`.
+
+ </description>
+ <priority>3</priority>
+ <example>
+ <![CDATA[
+public class Foo {
+ private void bar(String howdy) {
+ // howdy is not used
+ }
+}
+]]>
+ </example>
+ </rule>
+
+ <rule name="UnusedImports"
+ language="java"
+ since="1.0"
+ message="Unused import ''{0}''"
+ class="net.sourceforge.pmd.lang.java.rule.bestpractices.UnusedImportsRule"
+ typeResolution="true"
+ deprecated="true"
+ externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_bestpractices.html#unusedimports">
+ <description>
+ Reports import statements that are not used within the file. This also reports
+ duplicate imports, and imports from the same package. The simplest fix is just
+ to delete those imports.
+
+ This rule is deprecated since PMD 6.34.0. Use the rule {% rule "java/codestyle/UnnecessaryImport" %}
+ from category codestyle instead.
+ </description>
+ <priority>4</priority>
+ <example>
+ <![CDATA[
+import java.io.File; // not referenced or required
+import java.util.*; // not referenced or required
+public class Foo {}
+]]>
+ </example>
+ </rule>
+
+ <rule name="UnusedLocalVariable"
Review comment:
This rule is enabled in our repo
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[GitHub] [ignite-3] zstan commented on a change in pull request #327: review pmd check rules
Posted by GitBox <gi...@apache.org>.
zstan commented on a change in pull request #327:
URL: https://github.com/apache/ignite-3/pull/327#discussion_r705920281
##########
File path: check-rules/errorprone.xml
##########
@@ -0,0 +1,3721 @@
+<?xml version="1.0"?>
+
+<ruleset name="Error Prone"
+ xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+ xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
+
+ <description>
+ Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
+ </description>
+
+ <rule name="AssignmentInOperand"
+ language="java"
+ since="1.03"
+ message="Avoid assignments in operands"
+ class="net.sourceforge.pmd.lang.java.rule.errorprone.AssignmentInOperandRule"
+ externalInfoUrl="${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 && 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"
Review comment:
I stopped here, seems all upper is appropriate and very helpful.
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