title: Simple Scheduler using quartz getting Error in java
body: <p>I am trying to make Scheduler using Quartz. I have tried this example</p>
  
  <pre><code> JobDetail detail = new JobDetail();
   detail.setName("dummyJobName");
   detail.setJobClass(HelloWorld.class);
   System.out.println("Scheduler First Example");
   SimpleTrigger simpleTrigger = new SimpleTrigger();
   simpleTrigger.setName("dummyTriggerName");
   simpleTrigger.setStartTime(new Date(System.currentTimeMillis() + 1000));
   simpleTrigger.setRepeatCount(SimpleTrigger.REPEAT_INDEFINITELY);
   simpleTrigger.setRepeatInterval(10000);
   Scheduler scheduler = new StdSchedulerFactory().getScheduler();
   scheduler.scheduleJob(detail, simpleTrigger);
   scheduler.start();
  </code></pre>
  
  <p>but using this i am getting error like this.</p>
  
  <pre><code>Exception in thread "main" org.quartz.SchedulerException: 
                                             Job's group cannot be null
  </code></pre>
  
  <p>please can anybody Help me with this.?</p>