Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'").create();

checkRecord = gson.fromJson(checkString, CheckRecord.class);

String date = "2015-12-7T16:00:00.000Z"; 
date = date.replace("Z", " UTC");//注意是空格+UTC
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS Z");//注意格式化的表示式
Date d = format.parse(date );