Comment Terracotta - a Clustered JVM (Score 1) 680
Terracotta (an open-source solution to clustering at the JVM level) approaches this problem by recognizing that multi-threaded programs can become multi-JVM programs. Here's a great article just posted on Dr. Dobbs -> http://www.ddj.com/dept/java/199703478 with more details and links about Terracotta.
Disclaimer: I work for Terracotta.
Disclaimer: I work for Terracotta.