However, they are special in that they can read and write objects. The key to writing an object is to represent its state in a serialized form sufficient to reconstruct the object as it is read. Thus reading and writing objects is a process called object serialization .
Object serialization is essential to building all but the most transient applications.
Together use RMI to communicate. You can see object serialization used in that example to pass various objects back and forth between the client and server. You need to know about object serialization from two points of view. First, you need to know how to serialize objects by writing them to an ObjectOutputStream and reading them in again using an ObjectInputStream . The next section, Serializing Objects , shows you how.