private static void doemon(){
// 守护线程,当程序中只剩下守护线程时程序终止。
Thread t = new Thread(() -> {
for (int i = 0; i < 10; i++) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("i=" + i);
}
});
//t.setDaemon(true);//this is set t thread as a daemon thread.
t.start();
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("main thread exit.");
}