The old JDK 1.1 Developer's Guide had a page on the different thread models: https://docs.oracle.com/cd/E19455-01/806-3461/6jck06gqk/index.html https://docs.ora

The old JDK 1.1 Developer's Guide had a page on the different thread models: https://docs.oracle.com/cd/E19455-01/806-3461/6jck06gqk/index.html https://docs.oracle.com/cd/E19455-01/806-3461/6jck06gqk/inde... At the time, Solaris had the only "certified" JVM that did M:N threads, so they really liked to make a big deal about it. You could control N through a JNI call to thr_setconcurrency. Not portable, but it worked. That particular capability was almost always not helpful.