Linter for unused parameters in a Java project?

Question

CheckStyle had this option in the early versions: http://api.dpml.net/checkstyle/3.5/com/puppycrawl/tools/checkstyle/checks/usage/UnusedParameterCheck.html

Looking for a similar checker. Can anyone recommend me something?

Testing for this use case:


... main method .. 

        test("hello");
        return Longs.tryParse(request.getCategoryId());
    }

    @Nullable
    Long test(String unused) {
        System.out.println("Hello World");
        return null;
    }

I want the build to fail

Current CheckStyle version in use is 3.7. Not looking to downgrade.

Isn't the compilation going to fail when you try and run your automated tests (unit, integration, ...)? — ndc85430, Jan 06 '23 at 20:02
That doesn't even compile. Why do you need a linter for that? — Sören, Jan 06 '23 at 20:05
Does this answer your question? [How to check "The value of the local variable/field is not used" in Checkstyle?](https://stackoverflow.com/questions/20116032/how-to-check-the-value-of-the-local-variable-field-is-not-used-in-checkstyle) — Sören, Jan 07 '23 at 07:58
Unfortunately that does not catch unused params. I just tried it out — SagwaCat, Jan 10 '23 at 16:17

score 0 · Answer 1 · answered Feb 07 '23 at 09:56

Sonar Lint supports this as rule "java:S1172":

Unused method parameters should be removed - Unused parameters are misleading. Whatever the values passed to such parameters, the behavior will be the same.

But there are some exceptions to this rule.

The rule will not raise issues for unused parameters:

that are annotated with @javax.enterprise.event.Observes

in overrides and implementation methods

in interface default methods

in non-private methods that only throw or that have empty bodies

in annotated methods, unless the annotation is @SuppressWarning("unchecked") or @SuppressWarning("rawtypes"), inwhich case the annotation will be ignored

in overridable methods (non-final, or not member of a final class, non-static, non-private), if the parameter is documented with a properjavadoc.

Also Eclipse IDE supports this out of the box. This can be enabled in Java>Compiler>Errors/Warnings with option "Value of method parameter is not used" This produces info/warning/error (as you configure) "The value of the parameter XXX is not used"

Linter for unused parameters in a Java project?

1 Answers1