Sample Tree Data - The important aspect here is that the children objects be stored as elements in an array under a "children" key in the nested structure.

treeData.json

{
        "name": "MyClass",
        "children": [{
          "name": "1",
          "children": [{
            "name": "1",
            "children": [{
              "name": "7"
            }, {
              "name": "8"
            }, {
              "name": "9"
            }]
          }, {
            "name": "2",
            "children": [{
              "name": "7"
            }, {
              "name": "8"
            }, {
              "name": "9"
            }]
          }, {
            "name": "3"
          }]
        }, {
          "name": "2",
          "children": [{
            "name": "2",
            "children": [{
              "name": "2",
              "children": [{
                "name": "4"
              }, {
                "name": "5"
              }, {
                "name": "6"
              }]
            }, {
              "name": "5"
            }, {
              "name": "6"
            }]
          }, {
            "name": "5"
          }, {
            "name": "6"
          }]
        }, {
          "name": "3",
          "children": [{
            "name": "7"
          }, {
            "name": "8"
          }, {
            "name": "9"
          }]
        }]
      }