Dead Code

Symptoms

• A variable, parameter, field, code fragment, method, or class is not used anywhere (perhaps other than in tests).

Causes

• Requirements have changed, or new approaches are introduced, without adequate cleanup.

• Complicated logic results in some combinations of conditions that can't actually happen; you'll see this when simplifying conditionals.

What to Do

• Delete the unused code and any associated tests.

Payoff

Reduces size. Improves communication. Improves simplicity.

Contraindications

• If your application is a framework, you may have elements present to support clients' needs that, strictly speaking, aren't needed by the framework itself. For example, a class may have an empty hook method intended to be called by (not-yet-existing) subclasses.

Notes

This smell can be hard to detect without tool support. Once your suspicions are alerted, you can do things like a global search for new ClassName.