From JActor Consulting:
JID (Java Incremental Deserialization or reserialization) is a simple framework for deserialize the data. The key for fast deserializing is to deserialize only what you need and to keep the serialized data for items that have not been changed for reserialization after an update. Applications are built by subclassing existing JID actors and then composing more complex structures from them. The JID project includes a number of actors which support different types of persistent data.