Learn how to detect and fix thread leaks in Java applications using Java 21, thread dumps, ExecutorService, monitoring tools, and Spring Boot examples. Introduction Imagine running a restaurant where employees keep showing up for work but never leave. At first, everything seems fine. But after a few hours, the kitchen becomes crowded, employees bump into each other, and service slows down. Eventually, the restaurant stops functioning. That’s exactly what happens during a thread leak in Java applications . Threads are essential workers inside a Java application. They process web requests, background jobs, database operations, and scheduled tasks. But when threads are created and never properly terminated, they continue consuming memory and CPU resources forever.…