三个java程序--join用法

15年前 
//NO.1 
 public class ThreadTest implements Runnable {
  public static int a = 0;
  public void run() {
    for (int k = 0; k < 5; k++) {
      a = a + 1;
    }
  }
 
  public static void main(String[] args) {
    Runnable r = new ThreadTest();
    Thread t = new Thread(r);
    t.start();
    System.out.println(a);
  }
}
 
 
 
 
 
 
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//NO.2
public class ThreadTest implements Runnable {
  public static int a = 0;
  public void run() {
    for (int k = 0; k < 5; k++) {
      a = a + 1;
    }
  }
 
  public static void main(String[] args) throws Exception{
    Runnable r = new ThreadTest();
    Thread t = new Thread(r);
    t.start();
    t.join();
    System.out.println(a);
  }
}
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NO.3
public class ThreadTest implements Runnable {
  public void run() {
    for (int k = 0; k < 10; k++) {
      System.out.print(" " + k);
    }
  }
 
  public static void main(String[] args) throws Exception {
    Runnable r = new ThreadTest();
    Thread t1 = new Thread(r);
    Thread t2 = new Thread(r);
    t1.start();
    t1.join();
    t2.start();
  }
}