How BlockingQueue and Channels Work, From Runtime Down to the CPU

This installment of a concurrency programming series explains how blocking queues and channels hand messages between threads. It walks through the layers involved, from Java source and JDK classes like ArrayBlockingQueue and AQS, down through the JVM, OS thread parking, and x86-64 hardware. It describes how put and take operations rely on locks, condition waiting, and wakeup signals to coordinate producers and consumers. The article also explains how atomicity, visibility, and ordering guarantees are supported by atomic instructions, cache coherence, and acquire/release memory semantics. Go channels are presented alongside the Java model as a comparable handoff mechanism.