java多线程示例

java多线程示例：

package mythread;

public class ThreadTest {
    public static void main(String[] args) {
      Thread t1=new MyThreadA();
      Thread t2=new MyThreadA();
      Runnable mtb=new MyThreadB();
      Thread t3=new Thread(mtb);
      Thread t4=new Thread(mtb);
      t1.setName("Thread-1");
      t2.setName("Thread-2");
      t3.setName("Thread-3");
      t4.setName("Thread-4");
      t1.start();
      t2.start();
      t3.start();
      t4.start();
      //Thread.currentThread();//main thread
      System.out.println("main thread");
   }

}

class MyThreadA extends Thread{
   int i=0;
   public void run() {
      while(i<20){
         i++;
         for(int j=0;j<10000000;j++){
          ;
         }
         System.out.println(this.getName()+" i="+i);
      }
   } 
}

class MyThreadB implements Runnable{
   int i=0;
   public void run() {
      while(i<20){
         synchronized(this){
            if(i>=20){
             break;
          }
          i++;
          for(int j=0;j<10000000;j++){
             ;
          }
          System.out.println(Thread.currentThread().getName()+" i="+i);
       }
     }
   } 
}