Originally posted by arjun krishna: Can any body explain me what is the serialVersionUID ? Where it is used?
When you serialize an object to a datastream, one of the items created is a version ID. It is basically some sort of checksum based on the instance variables, their types, etc. They way, if you change the class, and try to create an instance from the serialize data, it will fail -- as the class has been changed.
Unfortunately, it may too sensitive. So they allow the programmer to create the checksum. If you add a variable "serialVersionUID", it will use that as the checksum, instead of calculating it.