difference between upcasting and downcasting

KBReddy · **Posted:** Mon Aug 08, 2011 8:26 pm

what is the difference between up-casting and down-casting

msi_333 · **Posted:** Wed Aug 10, 2011 2:27 pm

Code:

 
public class ExampleClass {

    public static void main(String[] args) {

        // Upcasting from subclass to super class.
        A aRef=new C();

        aRef.display();//Am in class C
        //Downcasting of reference to subclass reference.
        B bRef=(B) aRef;
        bRef.display();//Am in class C

        // Note the display function of class C is called because the type of object is class C

    }
}

interface A 
{
  void display();
}

class B implements A
{

    public void display() {
        System.out.println("Am in class B");
    }

}

class C extends B
{
    @Override
    public void display() {
        System.out.println("Am in class C");
    }
}

 

difference between upcasting and downcasting

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