difference between serializationa and externalization

[Anand Jain]

I have searched this question and found the reply as:

Serialization provides default mechanism for saving an object whereas in Externalization there is no default mechanism and we can control the process and have to override readExternal and writeExternal methods to save an object.

In serialization also we can override readObject and writeObject method to control the process of saving an object so where is the difference between serialization and externalization? Can somebody please throw some light on this?

[Campbell Ritchie]

Start with a copy of Thinking in Java™ by Bruce Eckel, which has a good explanation in.