title: toUpperCase in Java does not work
body: <p>I have a string:</p>
  
  <pre><code>String c = "IceCream";
  </code></pre>
  
  <p>If I use <code>toUpperCase()</code> function then it returns the same string, but I want to get <code>"ICECREAM"</code>. </p>
  
  <p>Where is the problem?</p>