In classes, code completion offers insertion of method overrides. For example in

    public class Foo
    {
        // caret here
    }

code completion offers overriding for the five overridable Object methods ("clone() - override" etc.).

In interfaces on the other hand nothing is offered, although overriding of methods is possible in interfaces as well, for example to specialize return types or to concretize a method's contract with a javadoc comment (like java.util.List.equals() does for example). One has to type the method declaration manually in those cases.