Your Java programs create and process various pieces of data or information. Some information is temporary, such as the visual elements of the AWT display; other pieces of information have meaning well beyond the execution lifetime of your program. In a traditional system, such permanent information is stored in files or databases; various conventions such as file types and extensions are used to identify the format of the data or the programs that can process the data. This model perpetuates the structured programming view of the separation of code and data.

In object-oriented languages such as Java, data and code are tightly bound together so that one does not exist without the other. To support permanent information in an object-oriented manner, you require a scheme to preserve the qualities of an object-oriented language when the object instances are temporarily written to a file and later restored. Persistence in an object-oriented programming language deals with the capability of objects to exist beyond the lifetime of the program that created them.

Introducing Object Persistence

Using Java Object Serialization

Making Your Objects Persistent

Looking Inside Object Serialization

Introducing Persistent Stores