title: Why doesn't my HashTable allow key collisions?
body: <p>I read that HashTable can map same key to multiple values. That's what collision is.</p>
  
  <p>Now I run the program like this:</p>
  
  <pre><code>Dictionary&lt;String,String&gt; hTable = new Hashtable&lt;String,String&gt;();
  hTable.put("a", "aa");
  hTable.put("a", "ab");
  System.out.println(""+hTable.get("a"));
  </code></pre>
  
  <p>My thinking says I should get <code>aa</code> and <code>ab</code>.</p>
  
  <p>But actual output is <code>ab</code></p>
  
  <p>Why is it so? Where is the collision then?</p>