class Tester {
            void test(Object s)    { System.out.println ("Object version");    }
            void test(Tester s)    { System.out.println ("Tester version");    }
            void test(SubTester s) { System.out.println ("SubTester version"); }
             
            // Not compilable any more if you uncomment the line 
            // since String and Tester are siblings
            // void test(String s) { System.out.println ("String version"); } 
             
            public static void main (String args[]) {
            Tester c = new Tester ();
            // Ambiguous, the most specific one which fit will be call
            c.test (null);         // SubTester version 
            c.test (new Object()); // Object version 
            }
            }
             
            class SubTester extends Tester{
            }