Part 2 of Java Thread Programming describes techniques for working with Java threads. It offers the best thread-pooling coverage and a great chapter on breaking out of blocked I/O.

After comparing Liberty’s existing thread management with the new Java Virtual Threads, we found that the existing Liberty thread pool produces comparable or often better performance for Liberty ...

JDK 21's virtual threads are a major leap forward for Java's concurrency model. Previously, Java relied on OS threads, which were resource-heavy, limiting how many threads could run concurrently.