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Aug 1, 2026 · Fundamentals

JVM Concurrency Deep Dive: JMM and Low‑Level Synchronization

This article explains the three fundamental problems of Java concurrency—visibility, atomicity, and ordering—describes how the Java Memory Model and happens‑before rules address them, and details the low‑level implementations and optimizations of volatile, synchronized, lock upgrading, and the removal of biased locking in JDK 15‑17.