create virtual thread

Thread thread = Thread.ofVirtual().name("myVirtual").start(runnable);

Thread thread = Thread.ofVirtual().name("myVirtual1").unstarted(runnable);
thread.start();

create virtual thread using ExecutorService

ThreadFactory factory = Thread.ofVirtual().name("myVirtual-", 0).factory();
try (ExecutorService executorService = Executors.newThreadPerTaskExecutor(factory)) {
    for (int i = 0; i < 10; i++) {
        executorService.submit(runnable);
    }
}

pinning

private final Runnable runnable = new Runnable() {
    @Override
    public void run() {
        log.info("1) run. thread: " + Thread.currentThread());
        synchronized (this) {  // <--- synchronized block cause pinning
            try {
                Thread.sleep(5000);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }
        log.info("2) run. thread: " + Thread.currentThread());
    }
};

detect pinning

-Djdk.tracePinnedThreads=full  or -Djdk.tracePinnedThreads=short

reentrantLock

private final ReentrantLock lock = new ReentrantLock();

private final Runnable runnable = new Runnable() {
    @Override
    public void run() {
        log.info("1) run. thread: " + Thread.currentThread());

        lock.lock();  // <-- use ReentrantLock instead of sycchronized block 
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            lock.unlock();
        }
        log.info("2) run. thread: " + Thread.currentThread());
    }
};

thread dump

jcmd <PID> Thread.dump_to_file -format=text <file>

spring boot

spring:
  threads:
    virtual:
      enabled: true

task execution

spring:
  task:
    execution:
      thread-name-prefix: myTask-

task scheduling

spring:
  task:
    scheduling:
      thread-name-prefix: myScheduler-

keep alive although only daemon thread run

spring:
  main:
    keep-alive: true

reference

https://docs.oracle.com/en/java/javase/21/core/virtual-threads.html

https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.2-Release-Notes#support-for-virtual-threads

https://d2.naver.com/helloworld/1203723

https://techblog.woowahan.com/15398/