Determine output:

class A{
	public void method1(){
		System.out.print("Class A method1");
	}
}
class B extends A{
	public void method2(){
		System.out.print("Class B method2");
	}
}
class C extends B{
	public void method2(){
		System.out.print("Class C method2");
	}	
	public void method3(){
		System.out.print("Class C method3");
	}
}
public class Test{
	public static void main(String args[]){
		A a = new A();
		C c = new C();		
		c.method2();
		a = c;
		a.method3();
	}
}

It is important to understand that it is the type of reference variable - not the type of the object that it refers to - that which determines what members can be accessed. That is, when a reference to a subclass object is assigned to a super class reference variable, we will have access only to those parts of the object defined by the superclass.
In the above program method method3() is defined in the class C which is a subclass of B and so A. Even the reference variable a refers to c, a can't access method3() as this method is unknown to class A.