Kilim is a message-passing framwork for Java that provides ultra-lightweight threads and facilities for fast, safe, zero-copy messaging between these threads.
The Java™ programming language made starting a new thread easier than ever before. But freeing your concurrent programs of obscure bugs is a different matter, and Java's programming model might not be the best available. A language called Erlang is getting some good press now in the areas of concurrency, distributed systems, and soft real-time systems.