Java 多线程:继承Thread类 和 实现Runnable接

多线程的两种实现方式：

1. 继承Thread类，并重写run() 方法:

MultiThread_ExtendsThread.java

package com.linyk3.test;

public class MultiThread_ExtendsThread extends Thread{
    //重写run方法
    @Override
    public void run() {
        int i = 0;
        while(i++ < 100) {
            System.out.println("I'm a thread that extends Thread!:" + i);
        }   
    }
}

2. 实现Runnable接口, 实现run()方法:
   MultiThread_ImplementsRunnable.java

package com.linyk3.test;

public class MultiThread_ImplementsRunnable implements Runnable{
    //实现run()方法
    public void run(){
        int i = 0;
        while(i++ < 100) {
            System.out.println("I'm a thread that implements Runnable!:" + i);
        }
    }
}

3. 测试类:
   package com.linyk3.test;
   MultiThread_TestMain.java

public class MultiThread_TestMain {
    public static void main(String[] args) {
                //直接启动线程类
        MultiThread_ExtendsThread t1 = new MultiThread_ExtendsThread();
        t1.start();
        //启动的是Thread类
        MultiThread_ImplementsRunnable r = new MultiThread_ImplementsRunnable();
        Thread t2 = new Thread(r);
        t2.start();
    }
}

运行结果:

I'm a thread that extends Thread!:1
I'm a thread that extends Thread!:2
I'm a thread that extends Thread!:3
I'm a thread that extends Thread!:4
I'm a thread that extends Thread!:5
I'm a thread that extends Thread!:6
I'm a thread that extends Thread!:7
I'm a thread that extends Thread!:8
I'm a thread that extends Thread!:9
I'm a thread that extends Thread!:10
I'm a thread that extends Thread!:11
I'm a thread that extends Thread!:12
I'm a thread that extends Thread!:13
I'm a thread that extends Thread!:14
I'm a thread that extends Thread!:15
I'm a thread that extends Thread!:16
I'm a thread that extends Thread!:17
I'm a thread that extends Thread!:18
I'm a thread that extends Thread!:19
I'm a thread that extends Thread!:20
I'm a thread that extends Thread!:21
I'm a thread that extends Thread!:22
I'm a thread that extends Thread!:23
I'm a thread that extends Thread!:24
I'm a thread that extends Thread!:25
I'm a thread that extends Thread!:26
I'm a thread that extends Thread!:27
I'm a thread that extends Thread!:28
I'm a thread that extends Thread!:29
I'm a thread that extends Thread!:30
I'm a thread that extends Thread!:31
I'm a thread that extends Thread!:32
I'm a thread that extends Thread!:33
I'm a thread that extends Thread!:34
I'm a thread that extends Thread!:35
I'm a thread that extends Thread!:36
I'm a thread that extends Thread!:37
I'm a thread that extends Thread!:38
I'm a thread that extends Thread!:39
I'm a thread that implements Runnable!:1
I'm a thread that implements Runnable!:2
I'm a thread that implements Runnable!:3
I'm a thread that implements Runnable!:4
I'm a thread that implements Runnable!:5
I'm a thread that implements Runnable!:6
I'm a thread that implements Runnable!:7
I'm a thread that implements Runnable!:8
I'm a thread that implements Runnable!:9
I'm a thread that implements Runnable!:10
I'm a thread that implements Runnable!:11
I'm a thread that implements Runnable!:12
I'm a thread that implements Runnable!:13
I'm a thread that implements Runnable!:14
I'm a thread that implements Runnable!:15
I'm a thread that implements Runnable!:16
I'm a thread that implements Runnable!:17
I'm a thread that implements Runnable!:18
I'm a thread that implements Runnable!:19
I'm a thread that implements Runnable!:20
I'm a thread that implements Runnable!:21
I'm a thread that implements Runnable!:22
I'm a thread that implements Runnable!:23
I'm a thread that implements Runnable!:24
I'm a thread that implements Runnable!:25
I'm a thread that extends Thread!:40
I'm a thread that implements Runnable!:26
I'm a thread that implements Runnable!:27
I'm a thread that implements Runnable!:28
I'm a thread that implements Runnable!:29
I'm a thread that implements Runnable!:30
I'm a thread that implements Runnable!:31
I'm a thread that implements Runnable!:32
I'm a thread that implements Runnable!:33
I'm a thread that implements Runnable!:34
I'm a thread that implements Runnable!:35
I'm a thread that implements Runnable!:36
I'm a thread that implements Runnable!:37
I'm a thread that implements Runnable!:38
I'm a thread that implements Runnable!:39
I'm a thread that implements Runnable!:40
I'm a thread that implements Runnable!:41
I'm a thread that implements Runnable!:42
I'm a thread that implements Runnable!:43
I'm a thread that implements Runnable!:44
I'm a thread that implements Runnable!:45
I'm a thread that implements Runnable!:46
I'm a thread that implements Runnable!:47
I'm a thread that implements Runnable!:48
I'm a thread that implements Runnable!:49
I'm a thread that implements Runnable!:50
I'm a thread that implements Runnable!:51
I'm a thread that implements Runnable!:52
I'm a thread that implements Runnable!:53
I'm a thread that implements Runnable!:54
I'm a thread that implements Runnable!:55
I'm a thread that implements Runnable!:56
I'm a thread that implements Runnable!:57
I'm a thread that implements Runnable!:58
I'm a thread that implements Runnable!:59
I'm a thread that implements Runnable!:60
I'm a thread that implements Runnable!:61
I'm a thread that implements Runnable!:62
I'm a thread that implements Runnable!:63
I'm a thread that implements Runnable!:64
I'm a thread that implements Runnable!:65
I'm a thread that implements Runnable!:66
I'm a thread that implements Runnable!:67
I'm a thread that implements Runnable!:68
I'm a thread that implements Runnable!:69
I'm a thread that implements Runnable!:70
I'm a thread that implements Runnable!:71
I'm a thread that implements Runnable!:72
I'm a thread that implements Runnable!:73
I'm a thread that implements Runnable!:74
I'm a thread that implements Runnable!:75
I'm a thread that implements Runnable!:76
I'm a thread that implements Runnable!:77
I'm a thread that implements Runnable!:78
I'm a thread that implements Runnable!:79
I'm a thread that implements Runnable!:80
I'm a thread that implements Runnable!:81
I'm a thread that implements Runnable!:82
I'm a thread that implements Runnable!:83
I'm a thread that implements Runnable!:84
I'm a thread that implements Runnable!:85
I'm a thread that implements Runnable!:86
I'm a thread that implements Runnable!:87
I'm a thread that implements Runnable!:88
I'm a thread that extends Thread!:41
I'm a thread that extends Thread!:42
I'm a thread that extends Thread!:43
I'm a thread that extends Thread!:44
I'm a thread that extends Thread!:45
I'm a thread that extends Thread!:46
I'm a thread that extends Thread!:47
I'm a thread that extends Thread!:48
I'm a thread that extends Thread!:49
I'm a thread that extends Thread!:50
I'm a thread that extends Thread!:51
I'm a thread that extends Thread!:52
I'm a thread that extends Thread!:53
I'm a thread that extends Thread!:54
I'm a thread that extends Thread!:55
I'm a thread that extends Thread!:56
I'm a thread that extends Thread!:57
I'm a thread that extends Thread!:58
I'm a thread that extends Thread!:59
I'm a thread that extends Thread!:60
I'm a thread that extends Thread!:61
I'm a thread that extends Thread!:62
I'm a thread that extends Thread!:63
I'm a thread that extends Thread!:64
I'm a thread that extends Thread!:65
I'm a thread that extends Thread!:66
I'm a thread that extends Thread!:67
I'm a thread that extends Thread!:68
I'm a thread that extends Thread!:69
I'm a thread that extends Thread!:70
I'm a thread that extends Thread!:71
I'm a thread that extends Thread!:72
I'm a thread that extends Thread!:73
I'm a thread that extends Thread!:74
I'm a thread that extends Thread!:75
I'm a thread that extends Thread!:76
I'm a thread that extends Thread!:77
I'm a thread that extends Thread!:78
I'm a thread that extends Thread!:79
I'm a thread that extends Thread!:80
I'm a thread that extends Thread!:81
I'm a thread that extends Thread!:82
I'm a thread that extends Thread!:83
I'm a thread that extends Thread!:84
I'm a thread that extends Thread!:85
I'm a thread that extends Thread!:86
I'm a thread that extends Thread!:87
I'm a thread that extends Thread!:88
I'm a thread that extends Thread!:89
I'm a thread that extends Thread!:90
I'm a thread that extends Thread!:91
I'm a thread that extends Thread!:92
I'm a thread that extends Thread!:93
I'm a thread that extends Thread!:94
I'm a thread that extends Thread!:95
I'm a thread that extends Thread!:96
I'm a thread that extends Thread!:97
I'm a thread that extends Thread!:98
I'm a thread that extends Thread!:99
I'm a thread that extends Thread!:100
I'm a thread that implements Runnable!:89
I'm a thread that implements Runnable!:90
I'm a thread that implements Runnable!:91
I'm a thread that implements Runnable!:92
I'm a thread that implements Runnable!:93
I'm a thread that implements Runnable!:94
I'm a thread that implements Runnable!:95
I'm a thread that implements Runnable!:96
I'm a thread that implements Runnable!:97
I'm a thread that implements Runnable!:98
I'm a thread that implements Runnable!:99
I'm a thread that implements Runnable!:100

最后:调用start()方法后并不是是立即的执行多线程的代码，而是使该线程变为可运行态，至于什么时候运行多线程代码是由操作系统决定的。