title: List.addAll throwing UnsupportedOperationException when trying to add another list
body: <p>List.addAll throwing <code>UnsupportedOperationException</code> when trying to add another list.</p>
  
  <pre><code>List&lt;String&gt; supportedTypes = Arrays.asList("6500", "7600"};
  </code></pre>
  
  <p>and in loop I am doing, </p>
  
  <pre><code>supportedTypes.addAll(Arrays.asList(supportTypes.split(","))); //line 2
  </code></pre>
  
  <p>reading <em>supportTypes</em> from a file.</p>
  
  <p>But line 2 throws a <code>UnsupportedOperationException</code>, but I am not able to determine why?</p>
  
  <p>I am adding another list to a list, then why this operation is unsupported?</p>