Multithreading in java

Programming in Java

Object Oriented in Java

Advanced topics in Java

With the help of multithreading, multiple threads may run simultaneously.
A thread is used to achieve multitasking and it is a light weight component.

main method is itself a thread in java.

class MainThreadDemo
{
 public static void main(String args[])
 {
  Thread t=Thread.currentThread();
  System.out.println("Thread details:"+t);
   //output main,5,main 
  t.setName("myThread");
  System.out.println("Name of thread"+t.getName());
  System.out.println("Priority of thread"+t.getPriority());
 }
}

Thread class may be created either by extending Thread class or implementing Runnable interface.

class NewThread implements Runnable {
 Thread t;
 NewThread() {
    // Create a new, second thread
   t = new Thread(this, "Demo Thread");
   System.out.println("Child thread: " + t);
   t.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);
        Thread.sleep(500);
  }
  } catch (InterruptedException e) {
      System.out.println("Child interrupted.");
  }
      System.out.println("Exiting child thread.");
  }
}

class ThreadDemo {
  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.");
  }
}

Ball moving game using Thread and applet.

import java.awt.*;
import java.applet.*
/*<applet code="game" widht=400 height=500>
</applet>
*/
public class game extends Applet implements Runnable
{
  Thread t;
  int i=10;
  public void init()
  {
    t= new Thread(this);
    t.start();
  }
  
  public void run()
  {
    for(; ; )//infinite loop
    {
      try
      {
        t.sleep(50)
        i=i+2;
        if(i>=400) //to check the ball goes outside the applet window.
         i=10;
        repaint();
      }
     catch(Exception ex)
     {
      
     }
    }
  }
  public void paint(Graphics g)
  {
    g.drawOval(i,20,40,40);
  }
}