java 多线程 、线程同步、线程异步dome

java 单线程，多线程、线程同步、线程异步 实现的二个方式 

1、继承Thread 类 跑线程 

public class ThreadSleepDemo extends Thread {
        public void run() {
            int j = 3;
            while (j-- != 0) {
                try {
                    Thread.sleep(100);
                } catch (Exception e) {}
                System.out.println("extends Thread j--：" + j);
            }
        }
    public static void main(String[] args) {
        ThreadSleepDemo demo = new ThreadSleepDemo();
        demo.run();
    }
}

 2、继承 实现 Runnable类 跑线程

 3、线程同步 （同步即排队执行）synchronized （安全事务锁）

 4、线程异步 （异步即同步执行）一起执行不排队

//线程池设置为3 个
public static ExecutorService exc = Executors.newFixedThreadPool(3);

public static void main(String[] args) {
    ThreadSleepDemo demo = new ThreadSleepDemo();
    exc.submit(demo);
    exc.submit(demo);
    exc.submit(demo);
    exc.shutdown();
    //关闭线程chi
    exc.shutdown();
}

以上是个人经验分享 有问题欢迎评论留言。