Java Examples - Checking a Thread


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Problem Description

How to check a thread is alive or not?

Solution

Following example demonstrates how to check a thread is alive or not by extending Threda class and using currentThread() method.

public class TwoThreadAlive extends Thread {
   public void run() {
      for (int i = 0; i < 10; i++) {
         printMsg();
      }
   }

   public void printMsg() {
      Thread t = Thread.currentThread();
      String name = t.getName();
      System.out.println("name=" + name);
   }

   public static void main(String[] args) {
      TwoThreadAlive tt = new TwoThreadAlive();
      tt.setName("Thread");
      System.out.println("before start(), tt.isAlive()=" + tt.isAlive());
      tt.start();
      System.out.println("just after start(), tt.isAlive()=" + tt.isAlive());
	
      for (int i = 0; i < 10; i++) {
         tt.printMsg();
      }
	
      System.out.println("The end of main(), tt.isAlive()=" + tt.isAlive());
	
   }
}

Result

The above code sample will produce the following result.

before start(), tt.isAlive()=false
just after start(), tt.isAlive()=true
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=main
name=Thread
name=main
name=Thread
The end of main(), tt.isAlive()=true
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread
name=Thread

java_threading.htm

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