title: Java string not converted to lower case
body: <p>Why does the string <code>s</code> print <code>"Hello, World"</code> after converting to lower case?</p>
  
  <pre><code>public class Practice {
      public static void main(String[] args){
          String s = "Hello, World";
          s.toLowerCase();
          System.out.println(s);
      }
  }
  </code></pre>