Affects PMD Version:
6.47.0

Rule:

Please provide the rule name and a link to the rule documentation:
Design.ImmutableField

Description:

ImmutableField sees an assignment that happens in a declaration or constructor, which would indicate the field may be final. But in the case where it is assigned in the declaration and constructor, it is no longer true that it may be final, but the rule still triggers.

Code Sample demonstrating the issue:

public class NotSoImmutableField {
    private int foo = 2;

    NotSoImmutableField() {
    }

    NotSoImmutableField(final int foo) {
        this.foo = foo;
    }

    public int getFoo() {
        return foo;
    }
}

Expected outcome:

The code is correct. PMD reports a violation:

[INFO] --- maven-pmd-plugin:3.17.0:check (basepom.default) @ wsj-util ---
[INFO] PMD version: 6.47.0
[INFO] PMD Failure: NotSoImmutableField:4 Rule:ImmutableField Priority:3 Private field 'foo' could be made final; it is only initialized in the declaration or constructor..

This warning is not correct. foo may not be final, since it is initialized both at declaration and in one of the constructors. Following the PMD recommendation results in a (correct) compiler error.

Running PMD through:
Maven