JBossSerialization is a new approach to java-serialization.
We (java developers) have accepted over the years java.io.ObjectInputStream and java.io.ObjectOutputStream being slow when dealing with writeObject operations.
We then started using Externalizable objects as a faster approach for serialization, but even that way was slow when using writeObject operations inside externalizable classes.
Recently we discovered that most of the problems in JavaSerialization are related to static synchronized caching, what causes CPU spikes and also diminishes scaling capabilities.
With JBossSerialization we have done internal benchmarks and we have realized at least 2 times faster serialization with this library. These benchmarks are commited into our CVS repository (as testcases).