code: public void validate () throws SchedulerException
    {
      if (m_sName == null)
      {
        throw new SchedulerException ("Trigger's name cannot be null");
      }
  
      if (m_sGroup == null)
      {
        throw new SchedulerException ("Trigger's group cannot be null");
      }
  
      if (m_sJobName == null)
      {
        throw new SchedulerException ("Trigger's related Job's name cannot be null");
      }
  
      if (m_sJobGroup == null)
      {
        throw new SchedulerException ("Trigger's related Job's group cannot be null");
      }
    }
docs: <p>
  Validates whether the properties of the <code>JobDetail</code> are valid
  for submission into a <code>Scheduler</code>.
  
  @throws IllegalStateException
  if a required property (such as Name, Group, Class) is not set.