title: Java 8 Stream String Null Or Empty Filter
body: <p>I've got Google Guava inside Stream:</p>
  
  <pre><code>this.map.entrySet().stream()
  .filter(entity -&gt; !Strings.isNullOrEmpty(entity.getValue()))
  .map(obj -&gt; String.format("%s=%s", obj.getKey(), obj.getValue()))
  .collect(Collectors.joining(","))
  </code></pre>
  
  <p>As you see there is a statement <code>!String.isNullOrEmpty(entity)</code> inside the filter function.</p>
  
  <p>I don't want to use Guava anymore in the project, so I just want to replace it simply by:</p>
  
  <pre><code>string == null || string.length() == 0;
  </code></pre>
  
  <p>How can I do it more elegant? </p>