如何在Java中找到给定类的所有子类？

import java.util.ArrayList;
import java.util.List;

public class FindSubclasses {
    public static void main(String[] args) {
        Class<?> parentClass = ParentClass.class;
        List<Class<?>> subclasses = findSubclasses(parentClass);
        for (Class<?> subclass : subclasses) {
            System.out.println("Subclass: " + subclass.getName());
        }
    }

    public static List<Class<?>> findSubclasses(Class<?> parentClass) {
        List<Class<?>> subclasses = new ArrayList<>();
        for (Class<?> clazz : parentClass.getClassLoader().getDefinedClasses()) {
            if (parentClass.isAssignableFrom(clazz) && !parentClass.equals(clazz)) {
                subclasses.add(clazz);
            }
        }
        return subclasses;
    }
}

class ParentClass {
}

class ChildClass1 extends ParentClass {
}

class ChildClass2 extends ParentClass {
}