Unused Method Parameter

ID

java.unused_method_parameter

Severity

low

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

Java

Tags

code-style, unused-code

Description

Reports method parameters that are never referenced in the method body. By default, @Override methods are excluded since parameters are mandated by the superclass or interface contract.

Rationale

Unused parameters bloat method signatures, confuse callers about what the method actually needs, and accumulate as dead code when interfaces or super-method contracts evolve. They also make the code harder to test, as callers must supply values that are simply discarded.

// Bad - 'unused' is never referenced
public void process(String used, int unused) {
    System.out.println(used);
}

// Good - all parameters used
public void process(String used, int count) {
    for (int i = 0; i < count; i++) {
        System.out.println(used);
    }
}

Remediation

Remove the unused parameter from the method signature, or use the parameter in the method body. If the parameter is required by an interface or override contract, consider prefixing it with an underscore or adding a comment explaining why it is intentionally unused.

References