You can only directly extend one class, yes. That class may extend another class, etc, so you may have many classes that are indirectly extended, but only one direct superclass. This seems like an introductory Java question, so I'm moving this thread 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