Failed to Load. System.ArgumentNullException: Argument cannot be null.

[ginxx009]

Hello guys here's the full error on my logcat

Failed to Load.
System.ArgumentNullException: Argument cannot be null.
Parameter name: s
at System.IO.StringReader..ctor (System.String s) [0x00000] in :0
at (wrapper remoting-invoke-with-check) System.IO.StringReader:.ctor (string)
at LitJson.JsonReader..ctor (System.String json_text) [0x00000] in :0
at LitJson.JsonMapper.ToWrapper (LitJson.WrapperFactory factory, System.String json) [0x00000] in :0
at LitJson.JsonMapper.ToObject (System.String json) [0x00000] in :0
at StreetUtility.LoadJsonFromStreamingAssets (System.String path_with_extention_under_streaming_assets_folder) [0x00000] in :0
notice.json

Could someone help me please . And here's my code.
StreetUtility.cs

        string full_path = Path.Combine(Application.streamingAssetsPath, 
        path_with_extention_under_streaming_assets_folder);
        string result;

        if (full_path.Contains("://") || full_path.Contains(":///"))
        {
            WWW www = new WWW(full_path);
            while (!www.isDone) { }
            result = www.text;
        }
        else
        {
            result = File.ReadAllText(full_path);
        }
        Debug.Log("Loaded file: " + result);
        JsonData itemData = JsonMapper.ToObject(json);

and here is my LocalizationManager.cs

        string json = StreetUtility.LoadJsonFromStreamingAssets("notice.json");
        if (json != null)
        {
        LitJson.JsonData data = LitJson.JsonMapper.ToObject(json);
        json = data[language.ToString()].ToJson();
        Debug.LogError("PK DEBUG on Language.toString() : " + json.ToString());
        notice = LitJson.JsonMapper.ToObject<string[]>(json);
        Debug.LogError("PK DEBUG on Notice.toString : " + notice.ToString());

And here's my json file

{
"EN": [
"Cancel is available with Cancel button.",
"If you succeed in a lottery, you can receive additional rewards.",
"Round 2 and 3 are shorter than you think.",
"Please check the homepage in Confirm Game Method and Change Member Information."
],
"KR": [
"Cancel 버튼으로 배팅 취소가 가능합니다.",
"로또에 성공하면 추가적인 보상을 받을 수 있습니다.",
"라운드 2와 3은 생각보다 시간이 짧습니다.",
"게임 방법 확인 및 회원정보 변경은 홈페이지에서 확인해주세요."
],
"CN": [
"[中文] Cancel is available with Cancel button.",
"[中文] If you succeed in a lottery, you can receive additional rewards.",
"[中文] Round 2 and 3 are shorter than you think.",
"[中文] Please check the homepage in Confirm Game Method and Change Member Information."
],
"HK": [
"[广东话] Cancel is available with Cancel button.",
"[广东话] If you succeed in a lottery, you can receive additional rewards.",
"[广东话] Round 2 and 3 are shorter than you think.",
"[广东话] Please check the homepage in Confirm Game Method and Change Member Information."
]
}

Please can someone help me please.