This library will allow you to search for class files given a package and also gives the ability to search for classes annotated with a specific annotation.
ClassFinderService finder = new ClassFinderServiceImpl();
Retrieves all the classes found within the given package
List <String>classesFound = finder.findClassesByPackage("com.mypackage");
Retrieves all classes annotated with TestAnnotation which could be on the class/field/method level
List <String> annotatedClassesFound = finder.findAnnotatedClassesInPackage("com.mypackage",TestAnnotation.class);