G1 is definitely an interesting piece of work. It's geared toward very large heaps where you need more predictable pause times, and is intended to replace the c

G1 is definitely an interesting piece of work. It's geared toward very large heaps where you need more predictable pause times, and is intended to replace the concurrent mark/sweep GC. To enable G1 on Java 7: -XX:+UseG1GC. Prepend -J if passing to the 'jruby' command.