Java: get all implementations of interface

gistfile1.java

interface Interface {}
class InterfaceImpl1 implements Interface {}
class InterfaceImpl2 implements Interface {}

class Main {
    private static List<Class<? extends Interface>> interfaceImplementations;
    
    static {
        interfaceImplementations = new ArrayList(Interface.class.getClasses()); // <- Doesn't work :(
    }
}