"Concurrency primitives" here is probably referring to Java's fundamental mutex system as used with `synchronized`, `wait()`, and `notify()`. Java's thread pool

"Concurrency primitives" here is probably referring to Java's fundamental mutex system as used with `synchronized`, `wait()`, and `notify()`. Java's thread pools and concurrent data structures are built on top of these and as you noted are relatively straightforward to use correctly, as they take care of the actual coordination of threads for you.