How to rewrite full updated json instead of only the nested part

I have a json file called test.json that looks like:

{
  "Added": {
    "type": "K",
    "newmem": {
      "IDNew": {
        "id": "777709",
        "type": "LOP"
      },
      "birthDate": "2000-12-09"
    },
    "code": "",
    "newest": {
      "curlNew": "",
      "addedForNew": ""
    }
  }
}

I am able to update the id in the json and write back to the file using the following code:

FileReader reader = new FileReader(filePath); //where file path = D://.../test.json
String keyToUpdate = "Added.newmem.IDNew.id"
String[] keyArr = jsonKey.split("\\." );
String keyToUpdate = keyArr [keyArr.length-1]
keyArr.removeElement(keyArr, keyToUpdate)
for (String key: keyArr){ 
   jsonObject = (JSONObject) jsonObject.get(key);
}

jsonObject.put("id",12345);
FileOutputStream outputStream = new FileOutputStream(filePath);
byte[] strToBytes = jsonObject.toString().getBytes();
outputStream.write(strToBytes);

However, instead of re-writing the entire json with the updated value, it's only writing:

  {
    "id": "777709",
    "type": "LOP"
  }

What can I do to re-write the entire json instead of only the nested part of it?

Your jsonObject before update only contains the "IDNew" node.

The best way to do this is using xPath from Jayway

private static final Configuration configuration = Configuration.builder()
    .jsonProvider(new JacksonJsonNodeJsonProvider())
    .mappingProvider(new JacksonMappingProvider())
    .build();



    String originalJson = "{\r\n"
    		+ "  \"Added\": {\r\n"
    		+ "    \"type\": \"K\",\r\n"
    		+ "    \"newmem\": {\r\n"
    		+ "      \"IDNew\": {\r\n"
    		+ "        \"id\": \"777709\",\r\n"
    		+ "        \"type\": \"LOP\"\r\n"
    		+ "      },\r\n"
    		+ "      \"birthDate\": \"2000-12-09\"\r\n"
    		+ "    },\r\n"
    		+ "    \"code\": \"\",\r\n"
    		+ "    \"newest\": {\r\n"
    		+ "      \"curlNew\": \"\",\r\n"
    		+ "      \"addedForNew\": \"\"\r\n"
    		+ "    }\r\n"
    		+ "  }\r\n"
    		+ "}";

JsonNode updatedJson = JsonPath.using(configuration).parse(originalJson).set("$.Added.IDNew.id", 12345).json();

System.out.println(updatedJson.toString());
}