在JAVA中使用DCL双检查锁机制实现单例的多线程安全

元旦放假期间学代码，我都感动我自己啦。

试过了，OK的。

package demo.thread;

public class MyObject {
	private static MyObject myObject ;
	private MyObject() {

	}
	public static MyObject getInstance() {
		try {
			if (myObject != null){

			} else {
				Thread.sleep(3000L);
				synchronized (MyObject.class) {
					if (myObject == null){
						myObject = new MyObject();
					}

				}

			}

		} catch (InterruptedException e) {
			e.printStackTrace();
		}

		return myObject;
	}

}

package demo.thread;

public class MyThread extends Thread {
	@Override
	public void run() {
		System.out.println(MyObject.getInstance().hashCode());
	}

}

package demo.thread;

public class Run {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		MyThread t1 = new MyThread();
		t1.start();

		MyThread t2 = new MyThread();
		t2.start();

		MyThread t3 = new MyThread();
		t3.start();

	}

}