Question

When a class [say A] is serialized all the subclasses which extends A will be serialized. Suppose in case of a scenario when the class A is extended by 2000 classes do the serialized object consists of all the subclass objects. By overriding the “private void writeObject” from subclass are we completely eliminating the parent object from getting serialized. Please confirm.

Thanks and Regards,
Subbu

Answer 1

When a class [say A] is serialized all the subclasses which extends A
will be serialized

No, the class A and its instance variables will be serialized, as long as the general contract of serialization is maintained.

Suppose in case of a scenario when the class A is extended by 2000
classes do the serialized object consists of all the subclass objects.

The serialized representation of a class does contain information about its supertypes. But not of its subclasses.

By overriding the “private void writeObject” from subclass are we
completely eliminating the parent object from getting serialized.
Please confirm.

No, overriding private void writeObject does not prevent the parent object from being serialized. Reference the Javadoc:

The writeObject method is responsible for writing the state of the
object for its particular class so that the corresponding readObject
method can restore it. The method does not need to concern itself with
the state belonging to the object’s superclasses or subclasses.