title: Concatenate object values regarding name of fields in alphabetical order
body: <p>I'm looking for a method to concatenate object values regarding name of fields in alphabetical order.</p>
  
  <p>Example:</p>
  
  <pre><code>public Class Request {
      private String number;
      private String amount;
      private String currency;
  }
  
  Request request = new Request();
  request.setNumber("tata");
  request.setCurrency("toto");
  </code></pre>
  
  <p>With this, my method should return <code>tototata</code>.</p>
  
  <p>Method must be generic:</p>
  
  <pre><code>public static String concatenate(Object object) { ...}
  </code></pre>
  
  <p><code>null</code> values must not be concatenated.</p>
  
  <p>I already checked out Apache Commons BeanUtils and Java 8 streams, but found nothing nice.</p>