Java Thread run() Method

Description

The Java Thread run() method is called if this thread was constructed using a separate Runnable run object, else this method does nothing and returns.

Declaration

Following is the declaration for java.lang.Thread.run() method

public void run()

Parameters

NA

Return Value

This method does not return any value.

Exception

NA

Example: Running a Thread implementing Runnable Interface

The following example shows the usage of Java Thread run() method. In this program, we've created a thread class ThreadDemo by implementing Runnable interface. In constructor, a new thread is created using new Thread. Using start(), the thread is started which in turn calls the run() method when thread is scheduled to run.

package com.tutorialspoint;

public class ThreadDemo implements Runnable {

   Thread t;
   ThreadDemo() {
    
      // thread created
      t = new Thread(this, "Admin Thread");
     
      // prints thread created
      System.out.println("thread  = " + t);
      
      // this will call run() function
      System.out.println("Calling run() function... ");
      t.start();
   }

   public void run() {
      System.out.println("Inside run() function");
   }

   public static void main(String args[]) {
      new ThreadDemo();
   }
} 

Output

Let us compile and run the above program, this will produce the following result −

thread = Thread[Admin Thread,5,main]
Calling run() function...
Inside run() function

Example: Running a Thread extending Thread Class

The following example shows the usage of Java Thread run() method. In this program, we've created a thread class ThreadDemo by extending Thread class. In constructor, a new thread is created using new Thread. Using start(), the thread is started which in turn calls the run() method when thread is scheduled to run.

package com.tutorialspoint;

public class ThreadDemo extends Thread {

   Thread t;
   ThreadDemo() {
    
      // thread created
      t = new Thread(this, "Admin Thread");
     
      // prints thread created
      System.out.println("thread  = " + t);
      
      // this will call run() function
      System.out.println("Calling run() function... ");
      t.start();
   }

   public void run() {
      System.out.println("Inside run() function");
   }

   public static void main(String args[]) {
      new ThreadDemo();
   }
} 

Output

Let us compile and run the above program, this will produce the following result −

thread = Thread[Admin Thread,5,main]
Calling run() function...
Inside run() function