This DEV Community article presents a custom Java EventBus implementation designed to decouple components through a publish-subscribe pattern. The code utilizes ConcurrentHashMap and CopyOnWriteArrayList to ensure thread safety, essential for high-concurrency applications. The SimpleEventBus class implements core methods for subscribing, unsubscribing, and pushing events to listeners.

This approach mirrors the functionality of libraries like Google Guava's EventBus but offers a lightweight, educational alternative. Understanding this pattern is vital for developers building modular, event-driven microservices or complex Java applications requiring efficient inter-component communication without tight coupling.