If you need to enter a section once atomically, do use one of the atomics as a switch.
Do not use cryptic sleep statements like Thread.sleep(2000) [...]
If two simple lines (or one depending on your format liking) are already inconsistent, imagine what a 500k codebase will look like.
Don't use getInstance() factory methods that in fact return new instances on every single call.
So you happen to work in an environment where you're behind a proxy.