第一种方式

package demo3;public class Threddemo {    public static void main(String[] args) {        MyThred mt = new MyThred();        mt.start();        for (int i = 0; i < 20; i++) {            System.out.println("main"+i);        }    }}public class MyThred extends Thread {    @Override    public void run() {        for (int i = 0; i < 20; i++) {            System.out.println("run"+i);        }    }}

第二种方式

package demo4;public class runableimpl implements Runnable {    @Override    public void run() {        for (int i = 0; i < 20; i++) {            System.out.println(Thread.currentThread().getName() + i);        }    }}public class demo01runable {    public static void main(String[] args) {//        runableimpl run = new runableimpl();//        Thread th = new Thread(run);//        th.start();//        Thread t = new Thread(new runableimpl());//        t.start();//        new Thread(){//            @Override//            public void run() {//                for (int i = 0; i < 20; i++) {//                    System.out.println(Thread.currentThread().getName()+i);//                }//            }//        }.start();        new Thread(new Runnable(){            @Override            public void run() {                for (int i = 0; i < 20; i++) {                    System.out.println(Thread.currentThread().getName()+i);                }            }        }).start();        for (int i = 0; i < 20; i++) {            System.out.println(Thread.currentThread().getName()+i);        }    }}

 lamda 表达式

new Thread(()-> System.out.println(Thread.currentThread().getName())).start();