🔸 TLDR
▪️ Queue = 1 message → 1 consumer (work distribution) ✅
▪️ Topic = 1 message → N subscribers (broadcast) 📣
▪️ Durable subscription = don’t miss messages while offline 🧷
🔸 CONTEXT (WHAT JMS IS, WITHOUT THE HYPE)
▪️ JMS is a Java API for messaging (asynchronous communication) between apps 📨
▪️ It’s about exchanging messages through a broker (ex: ActiveMQ, Artemis, IBM MQ…)
🧩 ▪️ Two main models: Queue (point-to-point) vs Topic (pub/sub) 🔀
🔸 MESSAGE QUEUES (POINT-TO-POINT) 📬
▪️ Producer sends to a queue
▪️ Consumers compete: each message is handled by only one consumer
▪️ Great for: background jobs, email sending, payments processing, retries ⚙️
Send a message to a queue
Receive a message from a queue
🔸 MESSAGE TOPICS (PUBLISH / SUBSCRIBE) 📣
▪️ Producer publishes to a topic
▪️ Every subscriber gets a copy (fan-out) 🌪️
▪️ Great for: domain events, notifications, cache invalidation, audit streams 🧠
Publish to a topic
Subscribe to a topic
🔸 TAKEAWAYS ✅
▪️ Use Queue when you want work to be processed once (load-balanced consumers) ⚖️
▪️ Use Topic when you want broadcast (many services react to the same event) 📡
▪️ Use Durable Subscribers when subscribers must not miss messages (even offline) 🧱
▪️ JMS is an API: behavior depends on your broker + config (delivery mode, ack, redelivery…) 🔧
🔸 QUESTION FOR YOU 🤔
▪️ In your projects: are you mostly Queue-first or Topic-first?
#Java #JMS #Messaging #EventDrivenArchitecture #Integration #Microservices #Backend #Architecture #JavaDevelopers #AsyncProcessing
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