asked on upcasting down casting object remains same but refernece changes
Hi,
When we do upcasting down casting and object instance why actual object still remains same but referenece changes? please advise
When we do upcasting down casting and object instance why actual object still remains same but referenece changes? please advise
JavaJava EEProgrammingProgramming Languages-OtherProgramming Theory
Last Comment
CPColin
Please link to where you read that.
ASKER
public class Casting {
public static void main(String[] args) {
// TODO Auto-generated method stub
Derived drv = new Derived();
Base base = (Base) drv;
System.out.println("Class : " + base.getClass());
}
}
public class Derived extends Base{
}
public class Base{
}
output is
Class : class Derived
i expected Base??
i expected Base?Why?
ASKER
package com.upcast;
class Base {
public Base() {}
public void foo() {
System.out.println("I'm the base!");
}
}
package com.upcast;
class Child extends Base {
public Child() {}
public void foo() {
System.out.println("I'm the child!");
}
}
package com.upcast;
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
Child x = new Child();
Base y = (Base) x;
y.foo();
}
}
I'm the child!
i expected I'm the base! (as reference is Base type)
ASKER
i expected Base?
Why?
since we upcaste to Base from Derived?
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ASKER
is it same with down casting? any good example on down casting? do we do down casting also often as upcasting?
It's the same with any casting.