Apache Maven PMD Plugin – Using Rule Sets

Using Rule Sets

The PMD plugin ships a default rule set, that has various rules enabled. The ruleset is available as /rulesets/java/maven-pmd-plugin-default.xml. See below for the rules, that are enabled with the default rule set.

There are many more rules available and bundled in the PMD code analysis tool:

To use other rule sets, you can configure it in the plugin as shown below. The rule sets may reside in the classpath, filesystem or at a URL. For rule sets that are bundled with the PMD tool, you do not need to specificy the absolute path of the file. It will be resolved by the plugin. But if the rule set is a custom rule set, you need to specify its absolute path.

See Understanding Rulesets if you want to create your own custom ruleset.

Note: Starting with PMD 5.0 and Maven PMD Plugin 3.0 the paths to the bundled rule sets for the Java language were changed from /rulesets/xyz.xml to /rulesets/java/xyz.xml. So when upgrading to Maven PMD Plugin 3.0 you may need to alter your plugin configuration.

Note: Starting with PMD 6.0.0 and Maven PMD Plugin 3.9.0, the rules have been reorganized into categories, e.g. /category/java/bestpractices.xml. So when upgrading to Maven PMD Plugin 3.9.0 you should review your plugin configuration and/or custom ruleset.

<project>
  ...
  <reporting>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-pmd-plugin</artifactId>
        <version>3.11.0</version>
        <configuration>
          <rulesets>
            <!-- A rule set, that comes bundled with PMD -->
            <ruleset>/category/java/bestpractices.xml</ruleset>
            <!-- Custom local file system rule set -->
            <ruleset>d:\rulesets\strings.xml</ruleset>
            <!-- Custom remote rule set accessed via a URL -->
            <ruleset>http://localhost/design.xml</ruleset>
          </rulesets>
        </configuration>
      </plugin>
    </plugins>
  </reporting>
  ...
</project>

The default ruleset

This is an excerpt of the ruleset /rulesets/java/maven-pmd-plugin-default.xml. It contains only rules for Java. If you use a different language, you'll need to specify your own custom ruleset.

The current version of the ruleset can be found in version control: https://gitbox.apache.org/repos/asf?p=maven-pmd-plugin.git;a=blob_plain;f=src/main/resources/rulesets/java/maven-pmd-plugin-default.xml;hb=HEAD

    <rule ref="category/java/bestpractices.xml/AvoidUsingHardCodedIP" />
    <rule ref="category/java/bestpractices.xml/CheckResultSet" />
    <rule ref="category/java/bestpractices.xml/UnusedImports" />
    <rule ref="category/java/bestpractices.xml/UnusedFormalParameter" />
    <rule ref="category/java/bestpractices.xml/UnusedLocalVariable" />
    <rule ref="category/java/bestpractices.xml/UnusedPrivateField" />
    <rule ref="category/java/bestpractices.xml/UnusedPrivateMethod" />

    <rule ref="category/java/codestyle.xml/DontImportJavaLang" />
    <rule ref="category/java/codestyle.xml/DuplicateImports" />
    <rule ref="category/java/codestyle.xml/ExtendsObject" />
    <rule ref="category/java/codestyle.xml/ForLoopShouldBeWhileLoop" />
    <rule ref="category/java/codestyle.xml/TooManyStaticImports" />
    <rule ref="category/java/codestyle.xml/UnnecessaryFullyQualifiedName" />
    <rule ref="category/java/codestyle.xml/UnnecessaryModifier" />
    <rule ref="category/java/codestyle.xml/UnnecessaryReturn" />
    <rule ref="category/java/codestyle.xml/UselessParentheses" />
    <rule ref="category/java/codestyle.xml/UselessQualifiedThis" />

    <rule ref="category/java/design.xml/CollapsibleIfStatements" />
    <rule ref="category/java/design.xml/SimplifiedTernary" />
    <rule ref="category/java/design.xml/UselessOverridingMethod" />

    <rule ref="category/java/errorprone.xml/AvoidBranchingStatementAsLastInLoop" />
    <rule ref="category/java/errorprone.xml/AvoidDecimalLiteralsInBigDecimalConstructor" />
    <rule ref="category/java/errorprone.xml/AvoidMultipleUnaryOperators" />
    <rule ref="category/java/errorprone.xml/AvoidUsingOctalValues" />
    <rule ref="category/java/errorprone.xml/BrokenNullCheck" />
    <rule ref="category/java/errorprone.xml/CheckSkipResult" />
    <rule ref="category/java/errorprone.xml/ClassCastExceptionWithToArray" />
    <rule ref="category/java/errorprone.xml/DontUseFloatTypeForLoopIndices" />
    <rule ref="category/java/errorprone.xml/EmptyCatchBlock" />
    <rule ref="category/java/errorprone.xml/EmptyFinallyBlock" />
    <rule ref="category/java/errorprone.xml/EmptyIfStmt" />
    <rule ref="category/java/errorprone.xml/EmptyInitializer" />
    <rule ref="category/java/errorprone.xml/EmptyStatementBlock" />
    <rule ref="category/java/errorprone.xml/EmptyStatementNotInLoop" />
    <rule ref="category/java/errorprone.xml/EmptySwitchStatements" />
    <rule ref="category/java/errorprone.xml/EmptySynchronizedBlock" />
    <rule ref="category/java/errorprone.xml/EmptyTryBlock" />
    <rule ref="category/java/errorprone.xml/EmptyWhileStmt" />
    <rule ref="category/java/errorprone.xml/ImportFromSamePackage" />
    <rule ref="category/java/errorprone.xml/JumbledIncrementer" />
    <rule ref="category/java/errorprone.xml/MisplacedNullCheck" />
    <rule ref="category/java/errorprone.xml/OverrideBothEqualsAndHashcode" />
    <rule ref="category/java/errorprone.xml/ReturnFromFinallyBlock" />
    <rule ref="category/java/errorprone.xml/UnconditionalIfStatement" />
    <rule ref="category/java/errorprone.xml/UnnecessaryConversionTemporary" />
    <rule ref="category/java/errorprone.xml/UnusedNullCheckInEquals" />
    <rule ref="category/java/errorprone.xml/UselessOperationOnImmutable" />

    <rule ref="category/java/multithreading.xml/AvoidThreadGroup" />
    <rule ref="category/java/multithreading.xml/DontCallThreadRun" />
    <rule ref="category/java/multithreading.xml/DoubleCheckedLocking" />

    <rule ref="category/java/performance.xml/BigIntegerInstantiation" />
    <rule ref="category/java/performance.xml/BooleanInstantiation" />