How to start a thread after specified time delay in java

java multithreading servletcontextlistener
Adi picture Adi · Nov 15, 2013 · Viewed 44.2k times · Source

I have called a method in ServletContextListener as thread ..Now as per my need i have to delay the thread for 1 minutes and then start executing the method called in the thread but i am not able to do that as i am very new in this...

Here is my code ...

public class Startup implements ServletContextListener {

@Override
public void contextDestroyed(ServletContextEvent sce) {
}

public void contextInitialized(ServletContextEvent sce) {
    // Do your startup work here
    System.out.println("Started....");
    //captureCDRProcess();
    new Thread(new Runnable() {

        @Override
        public void run() {

            captureCDRProcess();
        }
    }).start();

}

Please help me .. Thanks in advance..

Answer

TwoThe picture TwoThe · Nov 15, 2013

To do this properly, you need to use a ScheduledThreadPoolExecutor and use the function schedule like this:

final ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(NUM_THREADS);
executor.schedule(new Runnable() {
  @Override
  public void run() {
    captureCDRProcess();
  }
}, 1, TimeUnit.MINUTES);

Thread.sleep is not the way to go, because it does not guarantee that it wakes up after a minute. Depending on the OS and the background tasks, it could be 60 seconds, 62 seconds or 3 hours, while the scheduler above actually uses the correct OS implementation for scheduling and is therefore much more accurate.

In addition this scheduler allows several other flexible ways to schedule tasks like at a fixed rate or fixed delay.

Edit: Same solution using the new Java8 Lamda syntax:

final ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(NUM_THREADS);
executor.schedule(() -> captureCDRProcess(), 1, TimeUnit.MINUTES);

Related questions

Difference between wait() and sleep()

What is the difference between a wait() and sleep() in Threads? Is my understanding that a wait()-ing Thread is still in running mode and uses CPU cycles but a sleep()-ing does not consume any CPU cycles correct? Why …

Read More
"implements Runnable" vs "extends Thread" in Java

From what time I've spent with threads in Java, I've found these two ways to write threads: With implements Runnable: public class MyRunnable implements Runnable { public void run() { //Code } } //Started with a "new Thread(new MyRunnable()).start()" call Or, with …

Read More
How to properly stop the Thread in Java?

I need a solution to properly stop the thread in Java. I have IndexProcessorclass which implements the Runnable interface: public class IndexProcessor implements Runnable { private static final Logger LOGGER = LoggerFactory.getLogger(IndexProcessor.class); @Override public void run() { boolean run = true; …

Read More