Early Access: Java Concurrency With Project Loom
I am excited about Project Loom. The project focuses on easy to use lightweight concurrency for the JavaVM. Nowadays, the JavaVM provides a one java thread to one OS thread model to the programmer. While it's actually the current Oracle implementation, it used to be that many JavaVM versions ago, threads provided to the programmer were actually green threads.
Project Loom goes down that road again, providing lightweight threads to the programmer. Those lightweight threads are mapped to OS threads in a "many-to-many" relationship.