This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
First, please don't use so much bold. It's like shouting, and it makes your post unpleasant to read.
As for your question, please SearchFirst(←click) and come back with more specific questions after you've done some research if some particular point is not clear. The question has been discussed to death here and on other sites, and has plenty of coverage in tutorials, blogs, and whatnot. There's a good starting point right on this site: https://www.coderanch.com/how-to/java/InterfaceVsAbstractClass