Question

What is the use readObjectNoData in Serialization in java? Please explain with an example?
The java docs are not clear.

Answer 1

Quoting from “Effective Java”:

In case you’re curious, the readObjectNoData method was added in release
1.4 to cover a corner case involving the addition of a serializable superclass to an
existing serializable class. Details can be found in the serialization specification
[Serialization, 3.5].

If you implement a class with instance fields that is serializable and extendable,
there is a caution you should be aware of. If the class has invariants that
would be violated if its instance fields were initialized to their default values (zero
for integral types, false for boolean, and null for object reference types), you
must add this readObjectNoData method to the class:

// readObjectNoData for stateful extendable serializable classes
private void readObjectNoData() throws InvalidObjectException {
throw new InvalidObjectException("Stream data required");
}

Hope this helps…