Static Methods

Starting with Java 8, it's possible for an interface to provide an implemented static method.

public interface Fillable {
  double LITERS_PER_GALLON = 3.78541; // public static final field
  void fill(int amount);

  static double litersFromGallons(double gallons) {
    return gallons * LITERS_PER_GALLON;
  }
}

• A static interface method must have a method body; in an interface a method can't be both abstract and static.

• Remember that static methods can only access static fields; all interface fields are static (and public and final.)

Since they are not abstract, static methods don't change the interface's contract.

---

Prev -- Up -- Next