title: Jackson ObjectMapper not respecting configured date time format
body: <p>There's high probability I'm missing something, but, I'm unable to configure object mapper to use given date-time format. Parsing date-time string using same date formatter (that is used to configure object mapper) successfully parses the same date-time string. Here's relevant code.</p>
  
  <pre><code>    String eventTimeString = "2018-06-13 20:22:00";
      String jsonString = "{\"event_time\":\""+eventTimeString+"\"}";
  
      // configure date formatter
      SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
      sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
  
      // configure object mapper
      ObjectMapper mapper = new ObjectMapper();
      mapper.setDateFormat(sdf);
  
      // parse json string using configured object mapper
      Map&lt;String, Object&gt; jsonDataMap = mapper.readValue(jsonString, new TypeReference&lt;Map&lt;String, Object&gt;&gt;() {});
  
      // print event time class as parsed by object mapper
      System.out.println("event time class: " + (jsonDataMap.get("event_time").getClass().getName()));
  
      // test parsing date time field
      System.out.println(sdf.parse(eventTimeString));
  </code></pre>
  
  <p>The output that I get is:</p>
  
  <pre><code>event time class: java.lang.String
  Thu Jun 14 01:52:00 IST 2018
  </code></pre>
  
  <p>What am I doing wrong here?</p>
  
  <p>Thanks...</p>