java waiting in main method

public static void main(String[] args)
{
Test test = new Test();
  if(true){
  out.println("gone to wait! " + new Time(System.currentTimeMillis()));
  synchronized(test)
  {
    try
    {
      test.wait(1000*60*30);
    }
    catch(InterruptedException e)
    {
      e.printStackTrace();
    }
  }
  out.println("come back! " + new Time(System.currentTimeMillis()));
}
}

Linux sending process to background

ctrl+z
bg (enter)