Getting an overview of a Java program

Hey guys,

I'm a relatively inexperienced programmer. I have a project that involves working on a pretty complicated (IE many classes) Java application. I understand the language and most of its libraries, but my problem is with finding a quick way to get an overview of the program, its classes, inheritance and what they do. So far I've used Javadoc but I'm having trouble keeping track of what fields and methods have been inherited by child classes. Is there something out there like a UML diagram generator or anything that I can use to make understanding the program easier?

Thank you for your help.

Take a crap and before you flush, look in the toilet. That will give you a good overview of Java.