- Yes, HotSpot is “the real” thing and includes the best Oracle has. There is a JVM implementation from Azul too, which people consider to be excellent. - The

- Yes, HotSpot is “the real” thing and includes the best Oracle has. There is a JVM implementation from Azul too, which people consider to be excellent. - The case between Oracle and Google is not related to the code released by Sun/Oracle. - You can write heavily optimized code in Java that is as fast or faster than C, without using escape hatches. - There is no overhead for things you don't use (synchronization). - The JVM has probably the fastest general-purpose implementation for concurrency primitives for high-level languages. See for example: http://letitcrash.com/post/20397701710/50-million-messages-per-second-on-a-single-machine http://letitcrash.com/post/20397701710/50-million-messages-p... - The lack of tail calls is very annoying. The rest just works. -