title: How to parse json with retrofit in android
body: <p>please I need your help, I want to parse the following json in my app with retrofit in android, but the problem is that I don't know how to create my model classes,
  I want to show title, rankings, name, titre, difference and points of each ranking,</p>
  
  <p>My json:</p>
  
  <pre><code>    {
  "channel": {},
  "classification": [
              {
              "day": {
                  "id": "3169",
                  "accr": "J8",
                  "type": "0",
                  "title": "8ème journée",
                  "start": "2016-10-08",
                  "finish": "2016-10-09",
                  "poolid": "36",
                  "pool_name": null,
                  "rankings": {
                          "1": {
                              "club": {},
                              "evolution": {},
                              "difference": "77"
  
                              },
                          "2": {
                              "club": {},
                              "evolution": {},
                              "difference": "47"
  
                              },
                          "3": {
                              "club": {},
                              "evolution": {},
                              "difference": "61"
  
                              }
                      }
                  }
              }
          ]
  }
  </code></pre>
  
  <p>my top14</p>
  
  <pre><code>{
  "channel": {},
  "classification": [
              {
              "day": {
                  "id": "3169",
                  "accr": "J8",
                  "type": "0",
                  "title": "8ème journée",
                  "start": "2016-10-08",
                  "finish": "2016-10-09",
                  "poolid": "36",
                  "pool_name": null,
                  "rankings": {
                          "1": {
                              "club": {},
                              "evolution": {},
                              "difference": "77"
  
                              },
                          "2": {
                              "club": {},
                              "evolution": {},
                              "difference": "47"
  
                              },
                          "3": {
                              "club": {},
                              "evolution": {},
                              "difference": "61"
  
                              }
                      }
                  }
              }
          ]
  }
  </code></pre>
  
  <p>my top14lst</p>
  
  <pre><code>public class Top14List {
      @SerializedName("classification")
      @Expose
      private ArrayList&lt;Top&gt; classification = new ArrayList&lt;&gt;();
      public ArrayList&lt;Top&gt; getClassification() {
          return classification;
      }
      public void setClassification(ArrayList&lt;Top&gt; classification) {
          this.classification = classification;
      }
  }
  </code></pre>
  
  <p>my top</p>
  
  <pre><code>public class Top {
  
      private Map&lt;String, Day&gt; day;
  
      public Map&lt;String, Day&gt; getDay() {
          return day;
      }
  
      public void setDay(Map&lt;String, Day&gt; day) {
          this.day = day;
      }
  }
  </code></pre>
  
  <p>my Day </p>
  
  <pre><code>public class Day {
  
      private String title;
      private String start;
      private String finish;
  
      private Map&lt;String, Rankings&gt; rankings;
  
      public String getTitle() {
          return title;
      }
  
      public void setTitle(String title) {
          this.title = title;
      }
  
      public String getStart() {
          return start;
      }
  
      public void setStart(String start) {
          this.start = start;
      }
  
      public String getFinish() {
          return finish;
      }
  
      public void setFinish(String finish) {
          this.finish = finish;
      }
  
      public Map&lt;String, Rankings&gt; getRankings() {
          return rankings;
      }
  
      public void setRankings(Map&lt;String, Rankings&gt; rankings) {
          this.rankings = rankings;
      }
  }
  </code></pre>
  
  <p>my group</p>
  
  <pre><code>public class Group1 {
  
      private Map&lt;String, Club&gt; club;
      private String difference;
  
  
      public Map&lt;String, Club&gt; getClub() {
          return club;
      }
  
      public void setClub(Map&lt;String, Club&gt; club) {
          this.club = club;
      }
  
      public String getDifference() {
          return difference;
      }
  
      public void setDifference(String difference) {
          this.difference = difference;
      }
  
  
  }
  </code></pre>
  
  <p>but the problem i don't know how to code the ranking class "1" "2" "3"</p>
  
  <p>can you please help me</p>