Run Junit Test on a dynamically Loaded class

i have a problem at the moment doing a project at university. Basically i have to get the source code of a class , compile it and then execute a Junit test on it. I managed in many ways to compile dynamically my code, generating a .class file, so that's not the problem.

Since this procedure is done dynamically, how can i invoke methods and constructors of this class in the junit test case without using Java reflection?

Thanks in advance and sorry for my bad english!