Java's ExecutorService is a framework that simplifies the management of threads in Java applications. It allows developers to create a pool of threads, which can be reused to execute multiple tasks concurrently, improving performance and resource utilization. This service abstracts the complexities of thread management, enabling easier handling of asynchronous tasks. With ExecutorService, developers can submit tasks for execution and control their lifecycle, including scheduling and termination. It provides various implementations, such as ThreadPoolExecutor and ScheduledThreadPoolExecutor, catering to different use cases. This makes it a powerful tool for building scalable and efficient multi-threaded applications.