title: Jackson unable to Map Class using ObjectMapper
body: <p>I am trying to serialize a class which contains two strings and a map of string to strings using Jackson. Here is the json i am trying to serialize. I am wondering if there is a problem because I am trying to serialize empty arrays.</p>
  
  <pre><code>{
      "filters": {
          "test": [
              "hi"
          ],
          "groups": [],
          "groupsOT": [],
          "chains": [],
          "chainsOT": [],
          "locations": [],
          "locationsOT": [],
          "reports": [],
          "reportsOT": []
      },
      "fromDate": "09.03.2015",
      "toDate": "16.03.2015"
  }
  </code></pre>
  
  <p>Here is the class that is being used to try and serialize this.</p>
  
  <pre><code>public class FilterRequest{
      public String getToDate() {
          return toDate;
      }
  
      public void setToDate(String toDate) {
          this.toDate = toDate;
      }
  
      public String getFromDate() {
          return fromDate;
      }
  
      public void setFromDate(String fromDate) {
          this.fromDate = fromDate;
      }
  
      public Map&lt;String, String[]&gt; getFilters() {
          return filters;
      }
  
      public void setFilters(Map&lt;String, String[]&gt; filters) {
          this.filters = filters;
      }
  
      private String toDate;
      private String fromDate;
      private Map&lt;String,String[]&gt; filters;
  
      public FilterRequest(){
          filters = new HashMap&lt;String,String[]&gt;();
      }
  
  
  }
  </code></pre>
  
  <p>The code that is failing is simply</p>
  
  <pre><code>    ObjectMapper mapper = new ObjectMapper();
      FilterRequest requestParams = mapper.readValue(requestBody, FilterRequest.class);
  </code></pre>
  
  <p>The error I am getting is </p>
  
  <pre><code>No suitable constructor found for type [simple type, class com.aramburu.overall.web.controller.FilterController$FilterRequest]: can not instantiate from JSON object (need to add/enable type information?)
  at [Source: {"filters":{"test":["hi"],"groups":[],"groupsOT":[],"chains":[],"chainsOT":[],"locations":[],"locationsOT":[],"reports":[],"reportsOT":[]},"fromDate":"09.03.2015","toDate":"16.03.2015"}; line: 1, column: 2]
  </code></pre>