converting to the same class while comparing (equals(Obj)) & Adding a final class

1.) Converted 'success' and 'error' to String class while comparing it with another string while applying equals(Obj).

2.) Added a final class instead of implementing a constant interface.
Thanks ! I have got one to work on.

But then how do I remove these commits ?

Also, is there a way to squash commits from browser, using the GUI ?