Visibility vs. Atomicity

On volatile vs AtomicInteger: http://stackoverflow.com/questions/19744508/volatile-vs-atomic

Slides on threading and concurrency: http://www.slideshare.net/alexmiller/java-concurrency-gotchas-3666977

Java wait() releases synchronization lock

Threads calling wait() release the synchronization lock on the current instance, i.e. the method with synchronized keyword is allowed to be entered by other threads.
http://tutorials.jenkov.com/java-concurrency/starvation-and-fairness.html