Looking for a test case generation tool

I don't have much experience with any kind of testing tools for software. For an assignment, I'm required to "identify a test case generation tool and use it on any sample code."

The first part of my question is to clarify what a 'test case generation tool' is. To me, this sounds like a tool that goes through your code and automatically creates code to test your program.

Second, most of the tools I've found that claim to do this seem very outdated, like Google's CodePro Analytix. Most of the code I've written is in Java on Eclipse, so I was hoping to find a tool that would work for that environment. Does anyone have any suggestions for tools I can use?