One more remark : if you are planning to make more test with the Comparable interface, you should fulfill the compareTo requirements, or the collections supporing sorting (such as TreeSet) won't work properly. For example, the implementation of Sub.compareTo method is not correct, because a.compareTo(b) is not equal to - b.compareTo(a).
"Roadie Engineer", you have previously been warned on multiple occasions regarding adjusting your display name to meet JavaRanch standards. This is not optional, and this is your final warning. Adjust your display name to comply with the required standards prior to your next post.
Failure to comply will result in the removal of your account.