title: Get Hashtable Key of similar content but not reference
body: <p>I have some java code that looks like this: it uses a <code>Hashtable</code> to store data that corresponds to a three-dimensional point.</p>
  
  <pre><code>Hashtable&lt;ThreeDimensionalPoint,data&gt; table = new Hashtable&lt;ThreeDimensionalPoint,data&gt;();
  table.put(new ThreeDimensionlPoint(1,1,1),new data());
  table.get(new ThreeDimensionalPoint(1,1,1);
  </code></pre>
  
  <p>What I want to do is to get <code>data</code> back out of the hashtable, only knowing the coordinates of the <code>ThreeDimensionalPoint</code> object. Of course, the third line will not work, since <code>.get</code> matches keys by reference, not content of the object.</p>
  
  <p>Does anybody have a solution?the <code>ThreeDimensionalPoint</code>class has three integers that specify the coordinates.</p>