title: Is a set's "toArray" deterministic?
body: <p>Obviously, sets do not have any kind of ordering, so I cannot expect any specific ordering if I do</p>
  
  <pre><code>String[] string = mySet.toArray();
  </code></pre>
  
  <p>However, I am faced with a use case where I don't care what ordering the string array is in, but I DO need it to be the case that if two sets are equal to each other, then:</p>
  
  <pre><code>StringUtils.join(mySet.toArray(),',');
  </code></pre>
  
  <p>will produce the same exact string for those sets, always, no matter how many times I run the program assuming I stick with the same code.</p>
  
  <p>Do I have this guarantee?</p>
  
  <p>Similarly, does this whole true for the order that elements appear for a given Set in an iterator?</p>