title: String.split() generates a NullPointerException
body: <p>String.split() generates a NullPointerException.</p>
  
  <pre><code>BufferedReader brs = new BufferedReader(new InputStreamReader(System.in));
  String s1;
  String s2[];
  s1 = brs.readLine();
  s2 = s1.split(" ");
  </code></pre>