How to convert all json file. Program read path of JSON file

I try convert json file to object, it run when i use one trans-unit but appears problem when i try read two trans unit. Program read only path of json. I use JSONParser and JSONObject

        JSONParser jsonParser = new JSONParser();
        JSONObject obj = (JSONObject) jsonParser.parse(new FileReader(args[1]));

        JSONObject transUnit = (JSONObject) obj.get("trans-unit");
        id = (String) transUnit.get("id");
        if (id == null) {
            System.out.println("Id is required parameter!");
            return;
        }
        source = (String) transUnit.get("source");

        JSONObject targetList = (JSONObject) transUnit.get("target");
        if (targetList != null) {
            qualifier = (String) targetList.get("state-qualifier");
            targetText = (String) targetList.get("target-text");
        }
        JSONObject altTransList = (JSONObject) transUnit.get("alt-trans");
        if (altTransList != null) {
            extype = (String) altTransList.get("extype");
            match = (String) altTransList.get("match-quality");
            origin = (String) altTransList.get("origin");
            sourceAlt = (String) altTransList.get("source");
            targetAlt = (String) altTransList.get("target");
        }

It run, when I read json file below

 "trans-unit": {
  "id": "t1",
  "source": "Text text text text",
  "target": {
   "state-qualifier": "exact-match",
   "target-text": "Tekst tekst tekst tekst",
  },
  "alt-trans": {
   "extype": "exact-match",
   "match-quality": "100%",
   "source": "Text text text text",
   "target": "Tekst tekst tekst tekst"
  }
 }
}

But when a read this json:

{
  "trans-unit": {
    "id": "t1",
    "source": "Text text",
    "target": {
      "state-qualifier": "match",
      "target-text": "Tekst tekst"
    },
    "alt-trans": {
      "extype": "match",
      "match-quality": "100%",
      "source": "Text text",
      "target": "Tekst tekst"
    }
  },
  "trans-unit": {
    "id": "t2",
    "source": "Hello there.",
    "target": {
      "state-qualifier": "mt",
      "target-text": "Cześć"
    },
    "alt-trans": {
      "extype": "TRANSLATION",
      "match-quality": "nmt",
      "source": "Hello there.",
      "target": "Cześć"
    }
  }
}

JSON dont't read trans unit with id t1 but read only tran-unit t2.
I don't know where the problem lies. Can anyone help?

What do you really want to achieve?

I think the problem is, that the second json data is kind of List or Array.
So you only will get the last "object".

Are you allowed to use any library like gson ? This will make it a lot easier.