title: Jackson - converting java object to json - Need all key keys to upper case
body: <p>Need your help on conversion of java objects to json.
  current the json result showing all the key in small letter case, i need it to be upper case.</p>
  
  <pre><code>ObjectMapper mapper = new ObjectMapper();
  Writer strWriter = new StringWriter();
  mapper.writeValue(strWriter, obj);
  String jsonString= strWriter.toString();
  </code></pre>
  
  <p>and the result is </p>
  
  <pre><code>[{"flags":"1","name":"Peter","location":"London","startDate":"2012-01-06 00:00"}]
  </code></pre>
  
  <p>but i want results like this (all key key value should be in UPPER CASE):</p>
  
  <pre><code>[{"FLAGS":"YU","NAME":"Peter","LOCATION":"London","STARTDATE":"2012-01-06 00:00"}]
  </code></pre>
  
  <p>and also is it possible to get like this also (key first letter in upper case):</p>
  
  <pre><code>[{"Flags":"1","Name":"Peter","Location":"London","StartDate":"2012-01-06 00:00"}]
  </code></pre>
  
  <p>Can anyone help me on this.</p>
  
  <p>Thanks in advance.</p>