Why some interface methods are overriden by another interface?

Is it just for documentation purposes (e.g. Deque interface override all methods of the Queue interface, giving them another开发者_JAVA技巧 description), or there are other reasons ?

You can use it to enforce more specific method signatures and return types. Consider:

public interface Foo {
  Object result();
}

public interface Bar extends Foo {
  @Override
  String result(); // Bar redefines result() to return a String
}