JGroups has a finite number of types that need to get marshalled. If we describe them in an XML format (a la Google Protocol Buffers) and then generate the marshalling code, this has multiple advantages:

• Removal of boiler plate code
• Generation of Java code and C code (for wireshark)
• We can now make several classes immutable (all fields are final). Currently, we always have to read data from a stream (Streamable.readFrom()) and therefore cannot make all fields final
• Facory based approach: the factory code is generated and the right factory is picked based on the version number