ClassCastException

Question

i have two classes in java as:

class A {

 int a=10;

 public void sayhello() {
 System.out.println(\"class A\");
 }
}

class B extends A {

 int a=20;

 pub         


        

Answer 1

Once you create the object of a child class you cannot typecast it into a superClass. Just look into the below examples

Assumptions: Dog is the child class which inherits from Animal(SuperClass)

Normal Typecast:

Dog dog = new Dog();
Animal animal = (Animal) dog;  //works

Wrong Typecast:

Animal animal = new Animal();
Dog dog = (Dog) animal;  //Doesn't work throws class cast exception

The below Typecast really works:

Dog dog = new Dog();
Animal animal = (Animal) dog;
dog = (Dog) animal;   //This works

A compiler checks the syntax it's during the run time contents are actually verified