Is java object serialization compatible between 1.5 and 1.6

Question

I am wondering whether it is safe to mix jdk 1.5 and 1.6 (Java 6) object serialization (biderctional communication). I searched for an explicit statement from sun concerning

Answer 1

Have you read the Java Object Serialization Specification? There is a topic on versioning. There is also an article for class implementers: Discover the secrets of the Java Serialization API. Each release of Java is accompanied by compatibility notes.

From the Java 6 spec on serialization:

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The goals are to:

• Support bidirectional communication between different versions of a class operating in different virtual machines by:
  • Defining a mechanism that allows JavaTM classes to read streams written by older versions of the same class.
  • Defining a mechanism that allows JavaTM classes to write streams intended to be read by older versions of the same class.
• Provide default serialization for persistence and for RMI.
• Perform well and produce compact streams in simple cases, so that RMI can use serialization.
• Be able to identify and load classes that match the exact class used to write the stream.
• Keep the overhead low for nonversioned classes.
• Use a stream format that allows the traversal of the stream without having to invoke methods specific to the objects saved in the stream.

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