Anita, you keep posting questions in I/O and Streams regardless of whether the question has anything to do with I/O and Streams. Please take a look at our list of forums and try to select an appropriate forum for each different question you have. I will move this particular question to Java in General (beginner).
"I'm not back." - Bill Harding, Twister
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com
subject: difference between interface and abstract