Creating virtual threads

Definition

Since Java 21 you can start a virtual thread with Thread.startVirtualThread or Thread.ofVirtual(). It is used like a normal thread, but it is very cheap, so you create one per task instead of sharing a small pool.

Example code

Three ways to start a virtual thread

class Demo {
    public static void main(String[] args) throws InterruptedException {
        Thread first = Thread.startVirtualThread(() -> System.out.println("first runs on a virtual thread"));
        first.join();

        Thread second = Thread.ofVirtual().name("worker-1").start(
                () -> System.out.println(Thread.currentThread().getName() + ", virtual: " + Thread.currentThread().isVirtual()));
        second.join();

        Thread platform = Thread.ofPlatform().start(
                () -> System.out.println("a normal thread, virtual: " + Thread.currentThread().isVirtual()));
        platform.join();
    }
}

// Output:
// first runs on a virtual thread
// worker-1, virtual: true
// a normal thread, virtual: false