I have a class and I want to determine which classes are actually referenced from the class. Is there any easy way to determine which classes are being used directly? Ideally I should be able to know this before the class is compiled, but it is also valid to know this after the class have been compiled. I have a runtime system where the user can provide "sequences" that will be executed. These sequences will be executed in Java. However, we want to warn the user if he uses Java Classes that are not included in a pre-approved API.