A Brief History

Java had concurrency support from the begining.

Java 1(1996) includes the Thread class, the Runnable interface and the synchronized keyword. These features laid the foundation for multithreading in Java.

Java 5(2004) introduced the java.util.concurrency package with a comprehensive set of tools for concurrent programming including Future and Callable, Executors, Locks, Semaphore, Atomic Classes, Concurrent Collections, and BlockingQueue, making it easier to work with multithreading and reducing the complexity associated with manually managing threads.

Java 8(2014): Streams, CompletableFuture. CompletableFuture is currently the primary mechanism for concurrent programming in modern Java.

Java 9(2015): Reactive Stream

Java 21(2023): Virtual Threads (Actually Java had green threads at the begining, but switched to platform threads in version 1.2 in order to take full advantage of multi-core processors.)