为Java主方法执行创建了多少个线程？

Question

I have a java main method. I put the java main thread sleep for sometime.

public static void main(String[] args) {
    Thread.sleep(10);
}

Total, how many number of threads would be created for java main execution (including deamon thread)

Answer 1

Exactly one.

You can check it by adding a line:

System.out.println(Thread.activeCount());

Sleeping a thread creates no new threads:

sleep(long millis) Causes the currently executing thread to sleep (temporarily cease execution) for the specified number of milliseconds, subject to the precision and accuracy of system timers and schedulers.