执行一个hello-world-需要几个线程-

/**
 * 执行一个hello world 需要几个线程?
 * 1.Attach Listener
 * 2.Signal Dispatcher:    
 * 3.Finalizer:
 * 4.Reference Handler:
 * 5.main:
 *
 */
public class DefaultThread {
	private final static ThreadMXBean mBean = ManagementFactory.getThreadMXBean();
	public static void main(String[] args) {
		System.out.println("hello world");
		long[] allThreadIds = mBean.getAllThreadIds();
		ThreadInfo[] threadInfo = mBean.getThreadInfo(allThreadIds);
		for (ThreadInfo info : threadInfo) {
			System.out.print(info.getThreadName() + ":\t");
			System.out.println(info.getThreadState());
		}
	}
}

参考Java并发编程的艺术, 极客时间java专栏