2.How to implement Threads by extending Thread class in Java

 // Create a second thread by extending Thread  
 class NewThread extends Thread {  
   NewThread() {  
    // Create a new, second thread  
    super("Demo Thread");  
    System.out.println("Child thread: " + this);  
    start(); // Start the thread  
   }  
   // This is the entry point for the second thread.  
   public void run() {  
    try {  
      for(int i = 5; i > 0; i--) {  
       System.out.println("Child Thread: " + i);  
                // Let the thread sleep for a while.  
       Thread.sleep(500);  
      }  
    } catch (InterruptedException e) {  
      System.out.println("Child interrupted.");  
    }  
    System.out.println("Exiting child thread.");  
   }  
 }  
 class ExtendThread {  
   public static void main(String args[]) {  
    new NewThread(); // create a new thread  
    try {  
      for(int i = 5; i > 0; i--) {  
       System.out.println("Main Thread: " + i);  
       Thread.sleep(1000);  
      }  
    } catch (InterruptedException e) {  
      System.out.println("Main thread interrupted.");  
    }  
    System.out.println("Main thread exiting.");  
   }  
 }