title: Converting JSON to Hashmap<String, POJO> using GWT
body: <pre><code>SortedMap&lt;String, VehicleData&gt; hmap = new TreeMap&lt;String, VehicleData&gt;();
  </code></pre>
  
  <p>My JSON String sample:</p>
  
  <pre><code> {
      "3": {
          "Field1": 12,
          "Field2": "value",
          "Field3": null
      },
      "test": {
          "Field1": 20,
          "Field2": "value",
          "Field3": "vit"
      }
  }
  </code></pre>
  
  <p>I want to convert this string to HashMap declared above. Is there any method to convert directly from Json string to Hashmap?</p>