## Why is this an issue?

Testing equality of an enum value with `equals` is perfectly valid because an enum is an Object and every Java developer knows "==" should not be used to compare the content of an Object. At the same time, using "==" on enums:

- provides the same expected comparison (content) as `equals`
- is more null-safe than equals()
- provides compile-time (static) checking rather than runtime checking

For these reasons, use of "==" should be preferred to `equals`.

### Noncompliant code example

    public enum Fruit {
       APPLE, BANANA, GRAPE
    }

    public enum Cake {
      LEMON_TART, CHEESE_CAKE
    }

    public boolean isFruitGrape(Fruit candidateFruit) {
      return candidateFruit.equals(Fruit.GRAPE); // Noncompliant; this will raise an NPE if candidateFruit is NULL
    }

    public boolean isFruitGrape(Cake candidateFruit) {
      return candidateFruit.equals(Fruit.GRAPE); // Noncompliant; always returns false
    }

### Compliant solution

    public boolean isFruitGrape(Fruit candidateFruit) {
      return candidateFruit == Fruit.GRAPE; // Compliant; there is only one instance of Fruit.GRAPE - if candidateFruit is a GRAPE it will have the same reference as Fruit.GRAPE
    }

    public boolean isFruitGrape(Cake candidateFruit) {
      return candidateFruit == Fruit.GRAPE; // Compliant; compilation time failure
    }

## Resources

- Use == (or !=) to Compare Java Enums