title: Read only classes/methods
body: <p>In preparing for an interview, someone mentioned knowing how to make a class/method in java read-only.  I've been doing a bit of searching, but haven't found anything really concrete.</p>
  
  <p>Maybe this question is simpler to answer than I'm making it out to be, but what would be a way to make a class or method read-only in java?</p>