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.

Structured concurrency is a match for virtual threads, which is a lightweight implementation of threads provided by the JDK. A preview of virtual threads is planned for Java 19 this September.

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.