title: Parse JSON file using GSON
body: <p>I want to parse this <strong>JSON</strong> file in <strong>JAVA</strong> using <strong>GSON</strong> : </p>
  
  <pre><code>{
      "descriptor" : {
          "app1" : {
              "name" : "mehdi",
              "age" : 21,
              "messages": ["msg 1","msg 2","msg 3"]
          },
          "app2" : {
              "name" : "mkyong",
              "age" : 29,
              "messages": ["msg 11","msg 22","msg 33"]
          },
          "app3" : {
              "name" : "amine",
              "age" : 23,
              "messages": ["msg 111","msg 222","msg 333"]
          }
      }
  }
  </code></pre>
  
  <p>but I don't know how to acceed to the root element which is : <strong>descriptor</strong>, after that the <strong>app3</strong> element and finally the <strong>name</strong> element.</p>
  
  <p>I followed this tutorial <a href="http://www.mkyong.com/java/gson-streaming-to-read-and-write-json/">http://www.mkyong.com/java/gson-streaming-to-read-and-write-json/</a>, but it doesn't show the case of having a root and childs elements.</p>