// Builtin.java // Tests the built-in object methods class Test { int x; public Test(int x) { this.x = x; } } public class Builtin { public static void main(String[] args) { Test t1 = new Test(5); Test t2 = new Test(5); Test t3 = new Test(10); // since Test extends Object, it inherits several things: // 1. a toString method System.out.println("t1: " + t1); // 2. an equals method if (t1.equals(t2)) System.out.println("t1 == t2"); else System.out.println("t1 != t2"); if (t1.equals(t3)) System.out.println("t1 == t3"); else System.out.println("t1 != t3"); // 3. a getClass method System.out.println("t1 is " + t1.getClass()); } }