PMD - Unused Code Checks

This is the twentieth installment of explanation of PMD rules covering Unused Code Checks.

Unused Code Rules

The Unused Code Ruleset contains a collection of rules that find unused code.

UnusedPrivateField

Detects when a private field is declared and/or assigned a value, but not used.

Example

public class Something {

  private static int FOO = 2; // Unused

  private int i = 5; // Unused

  private int j = 6;

  public int addOne() {

    return j++;

  }

}

UnusedLocalVariable

Detects when a local variable is declared and/or assigned, but not used.

Example

public class Foo {

public void doSomething() {

  int i = 5; // Unused

}

}

UnusedPrivateMethod

Unused Private Method detects when a private method is declared but is unused.

Example

public class Something {

private void foo() {} // unused

}

UnusedFormalParameter

Avoid passing parameters to methods or constructors and then not using those parameters.

Example

public class Foo {

private void bar(String howdy) {

  // howdy is not used

}