Detects when a private field is declared and/or assigned a value, but not used. Since PMD 6.50.0 private fields are ignored, if the fields are annotated with any annotation or the enclosing class has any annotation. Annotations often enable a framework (such as dependency injection, mocking or e.g. Lombok) which use the fields by reflection or other means. This usage can't be detected by static code analysis. Previously these frameworks where explicitly allowed by listing their annotations in the property "ignoredAnnotations", but that turned out to be prone of false positive for any not explicitly considered framework. <pre> <code> public class Something { private static int FOO = 2; // Unused private int i = 5; // Unused private int j = 6; public int addOne() { return j++; } } </code> </pre> <a href="https://pmd.github.io/pmd-6.53.0/pmd_rules_java_bestpractices.html#unusedprivatefield"> See PMD documentation. </a>

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`. <pre> <code> public class Foo { private void bar(String howdy) { // howdy is not used } } </code> </pre> <a href="https://pmd.github.io/pmd-6.53.0/pmd_rules_java_bestpractices.html#unusedformalparameter"> See PMD documentation. </a>

Detects when a private field is declared and/or assigned a value, but not used. Since PMD 6.50.0 private fields are ignored, if the fields are annotated with any annotation or the enclosing class has any annotation. Annotations often enable a framework (such as dependency injection, mocking or e.g. Lombok) which use the fields by reflection or other means. This usage can't be detected by static code analysis. Previously these frameworks where explicitly allowed by listing their annotations in the property "ignoredAnnotations", but that turned out to be prone of false positive for any not explicitly considered framework. <pre> <code> public class Something { private static int FOO = 2; // Unused private int i = 5; // Unused private int j = 6; public int addOne() { return j++; } } </code> </pre> <a href="https://pmd.github.io/pmd-6.53.0/pmd_rules_java_bestpractices.html#unusedprivatefield"> See PMD documentation. </a>

In most cases, the Logger reference can be declared as static and final. _Note:_ This rule is deprecated since PMD 6.15.0 and will be removed with PMD 7.0.0. The rule is replaced by {% rule java/errorprone/ProperLogger %}. <pre> <code> public class Foo{ Logger log = Logger.getLogger(Foo.class.getName()); // not recommended static final Logger log = Logger.getLogger(Foo.class.getName()); // preferred approach } </code> </pre> <a href="https://pmd.github.io/pmd-6.53.0/pmd_rules_java_errorprone.html#loggerisnotstaticfinal"> See PMD documentation. </a>