The default behavior of Object.hashCode() is to return essentially the "address" of the object so that a.hashCode() == b.hashCode() if and only if a == b. How can I get this behavior in a user-defined class if a superclass already defines hashCode()? For instance:

class A {
  public int hashCode() {
    return 0;
  }
}

class B extends A {
  public int hashCode() {
    // Now I want to return a unique hashcode for each object.
    // In pythonic terms, it'd look something like:
    return Object.hashCode(this);
  }
}

Ideas?