title: Double in HashMap
body: <p>I was thinking of using a Double as the key to a HashMap but I know floating point comparisons are unsafe, that got me thinking. Is the equals method on the Double class also unsafe? If it is then that would mean the hashCode method is probably also incorrect. This would mean that using Double as the key to a HashMap would lead to unpredictable behavior.</p>
  
  <p>Can anyone confirm any of my speculation here?</p>