And given that you didn't know that, you really need to study them.
java.util.concurrent is one of the greatest gems of software ever written.
Is this method one of its gems? A cancel() which doesn't cancel? https://docs.oracle.com/javase/8/docs/api/java/util/concurre...
> Synchronized primitives don't compose. You can safely `synchronized get(...)` and safely `synchronized put(...)`. But their composition put(get(...)+1) isn't synchronized.
So is there anything in java.util.concurrent that does compose? put(get()) has exactly the same problem up here at the 'high level' (of CountdownLatches and Semaphores) as it does at the 'low level' (of synchronized methods.)
You can get a lot better nonblocking support with third party libraries. Like RxJS in javascript, RxJava is almost a requirement when doing non-blocking code.
You are right that true green threads would allow thread cancellation one day. Right now, Java can't because it relies on OS threads which aren't safe to cancel. Userspace threads don't have that problem
