title: How to decode JSON with unknown field using Gson?
body: <p>I have JSON similar to this : </p>
  
  <pre><code>{
    "unknown_field": {
      "field1": "str",
      "field2": "str",
      "field3": "str",
      "field4": "str",
      "field5": "str"
    }, ......
  }
  </code></pre>
  
  <p>I created classes to map this json </p>
  
  <pre><code>public class MyModel implements Serializable {
    private int id;
    private HashMap&lt;String, Model1&gt; models;
  
    // getters and setter for id and models here
  }
  </code></pre>
  
  <p>and class Model1 is a simple class only with String fields.</p>
  
  <p>But it doesn't work.</p>
  
  <p><strong>Edit</strong>: the <a href="http://textuploader.com/1a0l" rel="noreferrer">JSON format</a> looks like this: </p>
  
  <pre><code>{
      "1145": {
          "cities_id": "1145",
          "city": "Nawanshahr",
          "city_path": "nawanshahr",
          "region_id": "53",
          "region_district_id": "381",
          "country_id": "0",
          "million": "0",
          "population": null,
          "region_name": "Punjab"
      },
      "1148": {
          "cities_id": "1148",
          "city": "Nimbahera",
          "city_path": "nimbahera",
          "region_id": "54",
          "region_district_id": "528",
          "country_id": "0",
          "million": "0",
          "population": null,
          "region_name": "Rajasthan"
      }, 
      ...
  }
  </code></pre>