Question

How does the below code work?

     class A {
         int a = 10;
     }


     class B extends A implements Serializable{

      }



     public class Test {
       public static void main(String[] args){
        B obj = new B();
        obj.a = 25;


        //Code to serialize object B  (B b= new B()),
         // deserialize it and print the value of 'a'. 
      }
    }

The code prints 10 even though I have changed the value of ‘a’ in the code.

Any explanation for this behaviour ?

Answer 1

The default value of a is 10 – it will be set to 10 when the object is created. If you want to have a realistic test, set it to a different value after instantiation and then serialize it.

As for your update – if a class is not serializable, its fields are not serialized and deserialized. Only the fields of the serializable subclasses.