For storing objects in a database, I chose to serialize the objects in a way that maintains compatibility between object versions. So Java serialization was out. My first implementation was to serialize to JSON using Jackson, which was simple because it could serialize and deserialize objects that I was already using. However, there were more compact serialization schemes. Apache Thrift and Google Protocol Buffers looked fairly equivalent in functionality. Both required generating code from some IDL, making them less convenient than JSON. I chose Protocol Buffers since its serialization seemed to be slightly smaller than that of Thrift.

In order to continue using the objects that I was using before, since they included annotations and logic that can't be cleanly added to the protobuf-generated code, I used java.beans.Introspector to extract values from the objects to be stored in the database and put them into the protobuf objects and vice-versa.