// Demonstrate instanceof operator. class A { int i, j; } class B { int i, j; } class C extends A { int k; } class D extends A { int k; } #stuff class InstanceOf { public static void main(String args[]) { A a = new A(); B b = new B(); C c = new C(); D d = new D(); if(a instanceof A) System.out.println("a is instance of A"); if(b instanceof B) System.out.println("b is instance of B"); if(c instanceof C) System.out.println("c is instance of C"); if(c instanceof A) System.out.println("c can be cast to A"); if(a instanceof C) System.out.println("a can be cast to C"); System.out.println(); // compare types of derived types A ob; ob = d; // A reference to d System.out.println("ob now refers to d"); if(ob instanceof D) System.out.println("ob is instance of D"); System.out.println(); ob = c; // A reference to c System.out.println("ob now refers to c"); if(ob instanceof D) System.out.println("ob can be cast to D"); else System.out.println("ob cannot be cast to D"); if(ob instanceof A) System.out.println("ob can be cast to A"); else System.out.println(); // all objects can be cast to Object if(a instanceof Object) System.out.println("a may be cast to Object"); if(b instanceof Object) System.out.println("b may be cast to Object"); if(c instanceof Object) System.out.println("c may be cast to Object"); if(d instanceof Object) System.out.println("d may be cast to Object"); } }