Java Threads

Creating a Thread

There are two ways to create a thread.

It can be created by extending the Thread class and overriding its run() method:

  public class Main extends Thread {
  public void run() {
    System.out.println("This code is running in a thread");
  }
}       

Another way to create a thread is to implement the Runnable interface:

    
   class Main implements Runnable {
  public void run() {
    System.out.println("This code is running in a thread");
  }
}           

Running Threads

If the class extends the Thread class, the thread can be run by creating an instance of the class and call its start() method:

Use an iterator to remove numbers less than 10 from a collection:

               
            
  public class Main extends Thread {
  public static void main(String[] args) {
    Main thread = new Main();
    thread.start();
    System.out.println("This code is outside of the thread");
  }
  public void run() {
    System.out.println("This code is running in a thread");
  }
}
                 

If the class implements the Runnable interface, the thread can be run by passing an instance of the class to a Thread object's constructor and then calling the thread's start() method:

Use an iterator to remove numbers less than 10 from a collection:

               
          
 public class Main implements Runnable {
  public static void main(String[] args) {
    Main obj = new Main();
    Thread thread = new Thread(obj);
    thread.start();
    System.out.println("This code is outside of the thread");
  }
  public void run() {
    System.out.println("This code is running in a thread");
  }
}