步骤如下:

实现类:

package com.java.dayThread;

public class MyRunnable implements Runnable{
@Override
public void run() {
for (int i = 0; i < 20; i++) {
System.out.println(Thread.currentThread().getName()+i);
}
}
}

主方法:

package com.java.dayThread;
/*实现步骤:
1.创建一个Runnable接口的实现类
2.在实现类中,重写Runnable的run方法
3.创建一个Runnable接口实现类对象
4.创建Thread类对象,构造方法中传递Runnable接口的实现类对象
5.调用Thread类中的start方法,开启线程执行run方法
* */
public class ThreadDemo02 {
    public static void main(String[] args) {
        MyRunnable runnable = new MyRunnable();
        Thread thread = new Thread(runnable);
        thread.start();
        for (int i = 0; i < 20; i++) {
            System.out.println(Thread.currentThread().getName()+i);
        }
    }

}