title: Iteration of List<String> with modyfing String
body: <p>I can't modyfing element of List this way:</p>
  
  <pre><code>for (String s : list)
  {
     s = "x" + s;
  }
  </code></pre>
  
  <p>After execution this code elements of this list are unchanged
  How to achieve iteration with modyfing through List in the simplest way.</p>