import java.util.Timer;

import javax.servlet.ServletContextEvent;

import javax.servlet.ServletContextListener;

public class TestListener implements ServletContextListener {

  private Timer timer = null;

  public void contextInitialized(ServletContextEvent event) {

    timer = new Timer(true);

    timer.schedule(new TestTimer(), 0, 86400000);//milliseconds

  }

  public void contextDestroyed(ServletContextEvent event) {

    timer.cancel();

  }

}

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import java.util.TimerTask;

public class TestTimer extends TimerTask {

  public void run() {

    // do something ...

  }

}

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web.xml:

<listener>

<listener-class>test.TestListener</listener-class>

</listener>