EmptyFinalizer.java

import java.util.*;

public class EmptyFinalizer {
    static class A {
        protected void finalize() {
            System.out.println(this + " was finalized");
        }
    }

    static class B extends A {
    }

    static class C extends B {
        protected void finalize() { }
    }

    static class D extends C {
    }

    static class E extends D {
        protected void finalize() {
            System.out.println(this + " was finalized");
        }
    }

    public static void main(String[] args) {
        for (int i = 0; i < 5; i++) {
            new A();
            new B();
            new C();
            new D();
            new E();
        }

        for (int i = 0; i < 10; i++) {
            System.gc();
            try {
                Thread.sleep(100L);
            } catch (InterruptedException ie) { }
        }
    }
}