title: Possible null pointer exception in string utils
body: <p>I am using commons StringUtils.isNotBlank() to check if a string is not empty and blank. In some scenarios for a blank string or a null as input validation is not happening as expected. Null or blank is getting through.</p>
  
  <pre><code>   if( StringUtils.isNotEmpty(obj.getvalue()) ){
          .............
      }
  </code></pre>
  
  <p>When I go through the <a href="http://commons.apache.org/lang/api-2.5/org/apache/commons/lang/StringUtils.html" rel="nofollow">documentation of StringUtils</a> I found, </p>
  
  <blockquote>
    <p>A side effect of the null handling is that a NullPointerException
    should be considered a bug in StringUtils (except for deprecated
    methods).</p>
  </blockquote>
  
  <p>What dose it mean? It has got anything to do with my scenario?</p>