Can't wait to try this with JDK 6 u14!
In a recent podcast, James Gosling highlights the importance of G1 for certain kinds of large-scale Java applications, such as financial exchanges, which are characterised by large amounts of live heap data and considerable thread-level parallelism, and are often run on high-end multi-core processors:
"...the deep hidden secret about many of these Java apps is that they don't really use databases. Instead of databases they use huge amounts of RAM and push the garbage collector like mad because they cannot afford to touch the disk ever. When you are doing many, many thousands of transactions per second it's all about keeping everything in RAM, using hash tables, getting as many cores focused on the transactions as possible, and they usually have big issues about transaction latency."More details: http://www.infoq.com/news/2009/04/g1