At runtime, find all classes in a Java application that extend a base class

Question

I want to do something like this:

List animals = new ArrayList();

for( Class c: list_of_all_classes_available_to_my_app() )
   i         


        

Answer 1

I solved this problem pretty elegantly using Package Level Annotations and then making that annotation have as an argument a list of classes.

Find Java classes implementing an interface

Implementations just have to create a package-info.java and put the magic annotation in with the list of classes they want to support.