[twblalock]

I do concurrency in Java all the time with CompletableFuture and threadsafe data structures provided by various libraries, e.g. the Guava caches, and I rarely need to use locks or semaphores. It's a good set of abstractions that make concurrency pretty close to idiot-proof.

Futures in particular make it easy to write concurrent code close to the way you would write single-threaded code, because all of the threading is handled behind the scenes.