Making Child classes as Non Serializable in java

Question

I have a class which implements Serializable. Now I extends this class and I want this extended class to be non Serializable. So how to do it?

For example. I have

class A implements Serializable.

and I have

class B extends A.

But I want class B to be Non Serializable.

Answer 1

As others have made clear, it's not possible for a subclass of a Serializable class to be non-Serializable.

If what you want is for the subclass' attributes not to be serialized, one option is to make them all transient.

If you need more than that (you don't want super class fields to be serialized), override writeObject(ObjectOutputStream) and readObject(ObjectInputStream) as outlined here - https://web.archive.org/web/20120626144013/http://java.sun.com/developer/technicalArticles/ALT/serialization

Answer 2

You can't remove the interface, but you can prevent serialization at run-time:

class B extends A {
    private void writeObject(ObjectOutputStream oos) throws IOException {
        throw new NotSerializableException();
    }
}

Answer 3

That's indeed not possible. Your best bet is to let B composite/decorate A.

public class B {
    private A a = new A();

    public void doSomething() {
        a.doSomething();
    }
}

Answer 4

Not possible. Liskov Substitution Principle and all.