package corejava; class A1 { int i, j; } class B1 { int i, j; } class C1 extends A1 { int k; } class D1 extends A1 { int k; } class InstanceOfDemo { public static void main(String args[]) { A1 a = new A1(); B1 b = new B1(); C1 c = new C1(); D1 d = new D1(); if (a instanceof A1) System.out.println("a is instance of A"); if (b instanceof B1) System.out.println("b is instance of B"); if (c instanceof C1) System.out.println("c is instance of C"); if (c instanceof A1) System.out.println("c can be cast to A"); if (a instanceof C1) System.out.println("a can be cast to C"); System.out.println(); A1 ob; ob = d; // A reference to d System.out.println("ob now refers to d"); if (ob instanceof D1) 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 D1) System.out.println("ob can be cast to D1"); else System.out.println("ob cannot be cast to D1"); if (ob instanceof A1) System.out.println("ob can be cast to A1"); 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"); } }