title: Using Pairs or 2-tuples in Java
body: <p>My Hashtable in Java would benefit from a value having a tuple structure. What data structure can I use in Java to do that?</p>
  
  <pre><code>Hashtable&lt;Long, Tuple&lt;Set&lt;Long&gt;,Set&lt;Long&gt;&gt;&gt; table = ...
  </code></pre>