java jvm perf

http://www.oracle.com/technetwork/java/performance-138178.html

http://www.oracle.com/technetwork/java/javase/tech/index-jsp-140228.html

http://www.oracle.com/technetwork/java/javase/tech/index-jsp-140228.html

http://www.oracle.com/technetwork/java/javase/tech/index-jsp-136373.html