interface Base {
    CharSequence getId();
  }

  interface Sub extends Base {
    @Override
    String getId();
  }

  private static class ForwardingSub implements Sub {
    private final Sub delegate;

    ForwardingSub(Sub delegate) {
      this.delegate = delegate;
    }

    @Override
    public String getId() {
      return delegate.getId();
    }

    @Override

  interface Base {
    CharSequence getId();
  }

  interface Sub extends Base {
    @Override
    String getId();
  }

  private static class ForwardingSub implements Sub {
    private final Sub delegate;

    ForwardingSub(Sub delegate) {
      this.delegate = delegate;
    }

    @Override
    public String getId() {
      return delegate.getId();
    }

    @Override

      if (leftCode != rightCode) {
        return leftCode < rightCode ? -1 : 1;
      }

      // identityHashCode collision (rare, but not as rare as you'd think)
      int result = getUid(left).compareTo(getUid(right));
      if (result == 0) {
        throw new AssertionError(); // extremely, extremely unlikely.
      }
      return result;
    }

    @Override
    public String toString() {