title: Is JOptionPane.showMessageDialog thread safe?
body: <p>JOptionPane.showMessageDialog is supposed to be a useful utility for getting user feedback as it blocks your current thread while you wait.</p>
  
  <p>I would expect therefore that it would be thread-safe and that you wouldn't need to wrap the call in an invokeLater or an invokeAndWait.</p>
  
  <p>Is this the case?</p>