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JSON object is getting removed with remove method in JSON file instead of JSON array [duplicate]

This question already has answers here:
How to remove an element from JSON string in Java?
(2 answers)
Closed 6 months ago.
I am trying to remove JSON array from a JSON file using org.json library
I am trying to remove webAutomation JSON array from the JSON file as follows
{
"instructor": "Test_Instructor",
"url": "www.google.com",
"services": "Test Automation Service",
"expertise": "Testing",
"linkedIn": "linkedIn",
"courses": {
"webAutomation": [
{
"price": "500",
"courseTitle": "Selenium"
},
{
"price": "333",
"courseTitle": "Protractor"
}
],
"apiAutomation": [
{
"price": "344.00",
"courseTitle": "Rest Assured API Automation"
}
],
"mobileAutomation": [
{
"price": "4555",
"courseTitle": "Appium"
}
]
}
}
I tried following code. Here str has JSON file
JSONObject jsonObject = new JSONObject(str);
jsonObject.getJSONObject("courses").getJSONArray("webAutomation");
System.out.println("after removal");
String str2 = mapper.writeValueAsString(jsonObject);
System.out.println(str2);
This is removing the whole JSON object instead of just JSON Array.
The output is {"empty":false}
Please help

You can use remove method in org.json.JSONObject#remove.
JSONObject json = new JSONObject(str);
json.getJSONObject("courses").remove("webAutomation");
System.out.println(json);
The output will be:
{
"instructor": "Test_Instructor",
"url": "www.google.com",
"services": "Test Automation Service",
"expertise": "Testing",
"linkedIn": "linkedIn",
"courses": {
"apiAutomation": [
{
"price": "344.00",
"courseTitle": "Rest Assured API Automation"
}
],
"mobileAutomation": [
{
"price": "4555",
"courseTitle": "Appium"
}
]
}
}

Create a new Json file then append other Json files to it

Need to create a new json file (combined.json) then append multiple json files (json1 and json2) to combined.json.
Example:
Json 1 - previously created json file
[
{
"name":"John",
"city":"Berlin",
"cars":[
"audi",
"bmw"
],
"job":"Teacher"
}
]
Json2 - previously created json file
[
{
"name":"Mark",
"city":"Oslo",
"cars":[
"VW",
"Toyata"
],
"job":"Doctor"
}
]
Final product:
Combined.json - currenlty created json file
[
{
"name":"John",
"city":"Berlin",
"cars":[
"audi",
"bmw"
],
"job":"Teacher"
},
{
"name":"Mark",
"city":"Oslo",
"cars":[
"VW",
"Toyata"
],
"job":"Doctor"
}
]

Gson gson = new com.google.gson.Gson();
JSONArray combined = gson.fromJson(json1, JSONArray.class);
combined.addAll(gson.fromJson(json2, JSONArray.class));
// verify by looking on the value of: combined.toJSONString()

java8 hierarchy data json parsing and store in mongodb in flat format

I have json of 3 hierarchy which I want to store in mongodb. I want to store the data in flat format so that id could be generated for all the levels. Below is the json. each level data should store individually and when I get the data , I want the data in same relation. Please suggest how it can be achieved.
{
"data":[
{
"countryId":"1",
"countryName":"USA",
"cityList":[
{
"cityId": "11",
"cityName": "NY"
"userList": [
{
"userId": "111",
"userName": "user1"
},
{
"userId": "112",
"userName": "user2"
}
]
},{
"cityId":"12",
"cityName":"AC"
"userList": [
{
"userId": "121",
"userName": "user3"
},
{
"userId": "122",
"userName": "user4"
}
]
}
]
}
]
}
I want to store this data as mentioned below and should get the data in same hierarchy while retrieving
countryid countryname
cityid cityname
userid username

How to convert the tree structured json to Java object using gson

[
{
"sentence": "I want to buy shoes .",
"tree": {
"ROOT": [
{
"index": 2,
"token": "want",
"label": "VERB",
"pos": "VBP",
"tree": {
"nsubj": [
{
"index": 1,
"token": "I",
"label": "PRON",
"pos": "PRP"
}
],
"xcomp": [
{
"index": 4,
"token": "buy",
"label": "VERB",
"pos": "VB",
"tree": {
"aux": [
{
"index": 3,
"token": "to",
"label": "PRT",
"pos": "TO"
}
],
"dobj": [
{
"index": 5,
"token": "shoes",
"label": "NOUN",
"pos": "NNS"
}
]
}
}
],
"punct": [
{
"index": 6,
"token": ".",
"label": ".",
"pos": "."
}
]
}
}
]
}
}
]
This is tree represented in Json. But the keys for nested nodes keep changing.
For example "ROOT, nsubj, xcomp" ... etc.
How do I convert above json code to Java Object using gson.
Above response is from syntaxnet Parsey_Mcparseface api I'm trying to use.
Thanks in advance.

Gson has a method Gson#fromJson. For example, this is a code to read a simple String object.
Gson gson = new Gson();
String str = gson.fromJson("\"hello\"", String.class);
System.out.println("String: " + str);
You need to prepare Java Object to read your proposed JSON. But, you don't need to write code by yourself. There is a website providing automatical JSON object generator.
jsonschema2pojo
enter following items:
Target language: Java
Source type: JSON
Annotation type: Gson
and enter your class name, for example "ParsedSentence"
then, write code. You will get object.
Gson gson = new Gson();
ParsedSentence parsed = gson.fromJson(longLongJsonString, ParsedSentence.class);

Json : Content Parsing error

I have json file like this
[
{
"topic": "Example1",
"ref": {
"1": "Example Topic",
"2": "Topic"
},
"contact": [
{
"ref": [
1
],
"corresponding": true,
"name": "XYZ"
},
{
"ref": [
1
],
"name": "ZXY"
},
{
"ref": [
1
],
"name": "ABC"
},
{
"ref": [
1,
2
],
"name":"BCA"
}
] ,
"type": "Presentation"
}
]
I want to parse the ref array. I tried this. But showing error.
jsonArray.getJSONObject(index).getJSONArray("ref").getJSONObject(index).toString()
Now my question is
1) What is the correct way to parse that array's content.

The whole JSON is an array (starts with [). Its first element is an object (starts with {). This object has an attribute "ref". Its value is an object (starts with {).
So, to get this object, you need
jsonArray.getJSONObject(index).getJSONObject("ref")

I solved it By
JSONObject arJS = jsonArray.getJSONObject(index).getJSONObject("ref");
for(int counter = 1 ; jo<=jsonArray.getJSONObject(index).getJSONObject("ref").length();counter++){
String value = arJS.getString(String.valueOf(counter));
}