The join() method:

The join() method waits for a thread to die. In other words, it causes the currently running threads to stop executing until the thread it joins with completes its task.

Syntax:

public void join()throws InterruptedException

public void join(long milliseconds)throws InterruptedException

Example of join() method

class TestJoinMethod1 extends Thread{  

 public void run(){  

  for(int i=1;i<=5;i++){  

   try{  

    Thread.sleep(500);  

   }catch(Exception e){System.out.println(e);}  

  System.out.println(i);  

  }  

 }  

public static void main(String args[]){  

 TestJoinMethod1 t1=new TestJoinMethod1();  

 TestJoinMethod1 t2=new TestJoinMethod1();  

 TestJoinMethod1 t3=new TestJoinMethod1();  

 t1.start();  

 try{  

  t1.join();  

 }catch(Exception e){System.out.println(e);}  

  

 t2.start();  

 t3.start();  

 }  

}  

Output:1

       2

       4

       3
5

       2
1
       1
       2

       4
3
       3
       4
       5

       5

As you can see in the above example,when t1 completes its task then t2 and t3 starts executing.


Example of join(long miliseconds) method

class TestJoinMethod2 extends Thread{  

 public void run(){  

  for(int i=1;i<=5;i++){  

   try{  

    Thread.sleep(500);  

   }catch(Exception e){System.out.println(e);}  

  System.out.println(i);  

  }  

 }  

public static void main(String args[]){  

 TestJoinMethod2 t1=new TestJoinMethod2();  

 TestJoinMethod2 t2=new TestJoinMethod2();  

 TestJoinMethod2 t3=new TestJoinMethod2();  

 t1.start();  

 try{  

  t1.join(1500);  

 }catch(Exception e){System.out.println(e);}  

  

 t2.start();  

 t3.start();  

 }  

}  

Output:1

       2

       1

       3
4

       5
1
       2
       2

       4
3
       3
       4
       5

       5




In the above example,when t1 is completes its task for 1500 miliseconds(3 times) then t2 and t3 starts executing.


getName(),setName(String) and getId() method:

public String getName()
public void setName(String name)
public long getId()

class TestJoinMethod3 extends Thread{  
  public void run(){  
   System.out.println("running...");  
  }  
 public static void main(String args[]){  
  TestJoinMethod3 t1=new TestJoinMethod3();  
  TestJoinMethod3 t2=new TestJoinMethod3();  
  System.out.println("Name of t1:"+t1.getName());  
  System.out.println("Name of t2:"+t2.getName());  
  System.out.println("id of t1:"+t1.getId());  
  
  t1.start();  
  t2.start();  
  
  t1.setName("Sonoo Jaiswal");  
  System.out.println("After changing name of t1:"+t1.getName());  
 }  
}  





Output:Name of t1:Thread-0

       Name of t2:Thread-1

       running...

       id of t1:8

       After changling name of t1:Sonoo Jaiswal

       running...




The currentThread() method:

The currentThread() method returns a reference to the currently executing thread object.


Syntax:

public static Thread currentThread()


Example of currentThread() method




class TestJoinMethod4 extends Thread{  

 public void run(){  

  System.out.println(Thread.currentThread().getName());  

 }  

 }  

 public static void main(String args[]){  

  TestJoinMethod4 t1=new TestJoinMethod4();  

  TestJoinMethod4 t2=new TestJoinMethod4();  

  

  t1.start();  

  t2.start();  

 }  

}  




Output:Thread-0

       Thread-1