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JSONObject return empty:false

After some researchs, I didn't have found any solutions to this problem:
when I create a JSONObject (org.json) from a file, it return "empty":false. Why does it return this and how can I fix it?
Java:
JSONObject config = new JSONObject(Files.readAllLines(Paths.get("config/maj.json")));
JSON:
{"FyloZ":"0"}
Files.readAllLines is working return the right value.
Thanks!

Files.readAllLines() returns List<String>, not a String.
So actually you are using the following constructor (accepting a single Object parameter):
https://stleary.github.io/JSON-java/org/json/JSONObject.html#JSONObject-java.lang.Object-
Construct a JSONObject from an Object using bean getters
The only getter-style method of a List is isEmpty(), so you get that 'empty: false' thing.
Try the following:
String json = new String(Files.readAllBytes(Paths.get("config/maj.json")), "utf-8");
JSONObject config = new JSONObject(json);
Here we read JSON as bytes, convert them to a string (assuming it's in utf-8) and then create a JSONObject from it.

Parsing DBpedia JSON from localhost extraction server in java when the schema isn't known

This is probably a quick answer to a very novice question. I am having trouble wrapping my head around how to get JSON text dbpedia extraction server running from a localhost. The server is running fine, I followed the official instructions.
I have read the other StackOverflow questions about parsing JSON in java and what I am having trouble understanding is how to parse the JSON when the schema or structure is unknown.
For example in my code I try to grab the JSON from localhost and put it into a java object. But all the examples of parsing JSON online use a predesigned java object and all the JSON keys are mapped to an object's fields. (ie Employee class: name,job,email,id,phone)
String sURL = "http://localhost:9999/server/extraction/en/extract?title=" + wikipage + "&revid=&format=rdf-json&extractors=custom"; //just a string
URL url = new URL(sURL);
Reader pageReader = new InputStreamReader(url.openConnection().getInputStream());
Gson g = new Gson();
JsonReader jr = new JsonReader(new InputStreamReader((InputStream) request.getContent()));
jr.setLenient(true);
JsonParser jp = new JsonParser();
JsonElement root = jp.parse(new InputStreamReader((InputStream) request.getContent())); //convert the input stream to a json element
JsonObject rootobj = root.getAsJsonObject(); //may be an array, may be an object.
I now have this "json object" for the film "Blue Velvet" I can parse/iterate with jr.hasNext() or rootobj.getAsJsonArray().
Am I going about this correctly?
I feel like I am reinventing the wheel. Is there a standard way of parsing DBpedia JSON objects in Java?

At least the Jackson JSON library allows you to parse incoming JSON into a Map. If the keys and values of the JSON can be of any type, then you need to use Map<Object, Object>, which is a bit cumbersome, but anyways this should work:
ObjectMapper mapper = new ObjectMapper();
Map<Object, Object> parsedJSON = mapper.readValue(incomingJSON,
mapper.getTypeFactory().constructMapType(
LinkedHashMap.class,
Object.class,
Object.class));

How to have each record of JSON on a separate line?

When I use JSONArray and JSONObject to generate a JSON, whole JSON will be generated in one line. How can I have each record on a separate line?
It generates like this:
[{"key1":"value1","key2":"value2"}]
I need it to be like following:
[{
"key1":"value1",
"key2":"value2"
}]

You can use Pretty Print JSON Output (Jackson).
Bellow are some examples
Convert Object and print its output in JSON format.
User user = new User();
//...set user data
ObjectMapper mapper = new ObjectMapper();
System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(user));
Pretty Print JSON String
String test = "{\"age\":29,\"messages\":[\"msg 1\",\"msg 2\",\"msg 3\"],\"name\":\"myname\"}";
Object json = mapper.readValue(test, Object.class);
System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(json));
Reference : http://www.mkyong.com/java/how-to-enable-pretty-print-json-output-jackson/

You may use of the google-gson library for beautifying your JSON string.
You can download the library from here
Sample code :
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonParser jp = new JsonParser();
JsonElement je = jp.parse(uglyJSONString);
String prettyJsonString = gson.toJson(je);
OR
you can use org.json
Sample code :
JSONTokener tokener = new JSONTokener(uglyJsonString); //tokenize the ugly JSON string
JSONObject finalResult = new JSONObject(tokener); // convert it to JSON object
System.out.println(finalResult.toString(4)); // To string method prints it with specified indentation.
Refer answer from this post :
Pretty-Print JSON in Java

The JSON.stringify method supported by many modern browsers (including IE8) can output a beautified JSON string:
JSON.stringify(jsObj, null, "\t"); // stringify with tabs inserted at each level
JSON.stringify(jsObj, null, 4); // stringify with 4 spaces at each level
and please refer this : https://stackoverflow.com/a/2614874/3164682
you can also beautify your string online here.. http://codebeautify.org/jsonviewer

For gettting a easy to read json file you can configure the ObjectMapper to Indent using the following:
objectMapper.configure(SerializationFeature.INDENT_OUTPUT, true);

Convert from LinkedHashMap to Json String

I'm Workin with Mongo using Jongo, when I do a query I receive a LinkedHashMap as result.
Iterator one = (Iterator) friends.find(query).projection("{_id:0}").as(Object.class);
while (one.hasNext()) {
LinkedHashMap data = new LinkedHashMap();
data = (LinkedHashMap) one.next();
String content = data.toString();
}
the problem is that if the json is {"user":"something"} content will be {user=something}, it is not a json is only toString method from HashMap.
How I can get the original JSON?
I don't have a class to map the response and it isn't a solution create a map class, that is why I use a Object.class.

If you have access to some JSON library, it seems like that's the way to go.
If using org.json library, use public JSONObject(java.util.Map map):
String jsonString = new JSONObject(data).toString()
If Gson, use the gson.toJson() method mentioned by #hellboy:
String jsonString = new Gson().toJson(data, Map.class);

You can use Gson library from Google to convert any object to JSON. Here is an example to convert LinkedHashMap to json -
Gson gson = new Gson();
String json = gson.toJson(map,LinkedHashMap.class);

One of the com.mongodb.BasicDBObject constructors takes a Map as input. Then you just have to call the toString() on the BasicDBObject object.
Iterator one = (Iterator) friends.find(query).projection("{_id:0}").as(Object.class);
while (one.hasNext()) {
LinkedHashMap data= new LinkedHashMap();
data= (LinkedHashMap) one.next();
com.mongodb.BasicDBObject bdo = new com.mongodb.BasicDBObject(data);
String json = bdo.toString();
}

I resolved the problem using the following code:
Iterator one = (Iterator) friends.find(query).projection("{_id:0}").as(Object.class);
while (one.hasNext()) {
Map data= new HashMap();
data= (HashMap) one.next();
JSONObject d = new JSONObject();
d.putAll(data);
String content=d.toString();
}

if(data instanceof LinkedHashMap){
json=new Gson.toJson(data,Map.class).toString();
}
else{
json=data.toString();
}
return Document.parse(json);

How to extract json from a json string using GSON?

Below is my JSON String. I am trying to extract hosts from it.
{"description":"DescA","process_running":"sf","hosts":{"dc1":["machineA","machineB"]}}
Since hosts is a JSON String in itself and I would like to extract that JSON String from it. I am using GSON here -
String ss = new String(bytes, Charset.forName("UTF-8"));
// here ss is the above JSON String
Map<String, Object> data = gson.fromJson(ss, Map.class); // parse
I was trying to use Map to deserialize but the result it coming like this in the data-
{description=DescA, process_running=sf, hosts={dc1=[machineA, machineB]}}
Is there any way, I can extract hosts in the JSON format?

The easiest way I can think of to do this would be to use gson to create a tree of json elements from your map, and ask it to give you just the hosts node:
Map<String, Object> data = gson.fromJson(ss, Map.class); // parse
JsonObject jsonTree = (JsonObject) gson.toJsonTree(data);
String hostsJson = jsonTree.get("hosts").toString();