Are you a fine "connoisseur" of Java multithreading? If so, you should know the difference between those three concepts: volatile, synchronized, and AtomicInteger... 🧠
🔸 TL;DR
▪️ volatile 👉 guarantees visibility of a variable across threads, but does NOT make compound operations atomic.
▪️ synchronized 👉 provides mutual exclusion + visibility via a lock (monitor). Safe, but can be blocking and less scalable.
▪️ AtomicInteger 👉 offers lock-free atomic operations (e.g. incrementAndGet()) using CAS, great for highly contended counters. 🚀
🔸 VOLATILE – VISIBILITY ONLY 🫥
▪️ Ensures reads see the latest write across threads.
▪️ Does not protect from race conditions on x++, balance = balance + 1, etc.
▪️ Good for simple flags (e.g. running, shutdownRequested).
🔸 SYNCHRONIZED – MUTUAL EXCLUSION 🔐
▪️ Only one thread at a time can execute a synchronized block/method on a given monitor.
▪️ Ensures both visibility (happens-before rules) and atomicity of the critical section.
▪️ Simpler mental model, but can lead to contention and thread blocking under load.
🔸 ATOMICINTEGER – LOCK-FREE ATOMIC OPS ⚡
▪️ Uses Compare-And-Set (CAS) under the hood, no explicit lock.
▪️ Perfect for counters, metrics, ids (incrementAndGet(), addAndGet()…).
▪️ Scales better than synchronized for hot counters, but only for operations it exposes (no magic for arbitrary logic).
🔸 TAKEAWAYS ✅
▪️ Use volatile for “is it updated & visible?” flags, not for counters or complex state.
▪️ Use synchronized for critical sections where multiple fields must be updated consistently.
▪️ Use AtomicInteger when you need fast, thread-safe numeric updates without full locking.
▪️ Always think in terms of visibility + atomicity + contention when picking your tool. 🧠
#Java #JavaConcurrency #Multithreading #AtomicInteger #Synchronized #Volatile #CleanCode #JavaDeveloper
Go further with Java certification:
Java👇
Spring👇
SpringBook👇