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how to print Original request body JSON without any modification in java?

Normally to print out request body i using ObjectMapper, but this way removing space and printing object to string in one line, example :
if i send request body like this :
{
"Header" : "value"
}
and i using objectMapper to print that object
ObjectMapper mapper = new ObjectMapper();
mapper.writeValueAsString(requestBody)
the out put is like this :
{"Header":"value"}
how to print Original request body without any modification ?

I'm not sure if you can print it in it's original form but you can pretty print it.
With Jackson's Object Mapper, you can do something like:
ObjectMapper mapper = new ObjectMapper();
String json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(body);
System.out.println(json);
or
ObjectMapper mapper = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);
String json = mapper.writeValueAsString(body);
System.out.println(json);

I don't think you can do this without using any framework.
But you can use the gson for this if you enable the prettyPrinting option. Example:
Gson gson = new GsonBuilder()
.setPrettyPrinting()
.create();
prettyPrintedString = gson.toJson(requestBody, Object.class);

Parsing unquoted JSON keys using org.json.simple in Java

I have a JSON stored in a string.
String data = "{code: '0', distCode: '123'}";
I need to get the values of code, distCode. But when I try to parse it as below
JSONParser parser = new JSONParser();
JSONObject Details = (JSONObject) parser.parse(data);
Unexpected character (c) at position 2 exception is thrown.
I am sure it is because of unquoted keys in the string. How to parse the string into an JSON object using org.json.simple library?

Could not find way to achieve it using org.json.simple library. Finally done it using jackson libraries.
String data = "{code: '0', distCode: '123'}";
ObjectMapper mapper = new ObjectMapper();
mapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
mapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
Map<String, String> Shop_Details = mapper.readValue(data), Map.class);

How to write an Object to a JSON file in Java?

I am creating a program whereby I need to save(write) objects to a JSON, and then load(read) these objects back into the program. I have told that GSON is a good way to do this. However, I am having some troubles with it. I have tried the following:
Gson g = new Gson();
try (FileWriter writer = new FileWriter(file)) {
String j = g.toJson(board);
writer.write(j);
writer.flush();
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
When I run the program, I get the error:
class object3 declares multiple JSON fields named state
The object I am trying to write to the JSON has an ID, and an Array of another Object (object2), and each of these objects have an Array of another Object (object3). object3 has multiple fields, mostly strings. What is the simplest way for me to write an object such as this to a JSON file and then be able to read it back into my program?

If you simply want to serialize and deserialize object state in a JSON format, and don't care too much about the exact shape of the JSON, XStream makes this very easy. It tolerates almost any Java object structure and isn't as pernickety as Gson.
It was originally designed to serialize to XML, but if you use the JettisonMappedXmlDriver it will output JSON instead. I have found it to be a well-written and reliable library.
Product product = new Product("Banana", "123", 23.00);
XStream xstream = new XStream(new JettisonMappedXmlDriver());
xstream.setMode(XStream.NO_REFERENCES);
xstream.alias("product", Product.class);
System.out.println(xstream.toXML(product));
Produces:
{"product":{"name":"Banana","id":123,"price":23.0}}
To read it back in:
XStream xstream = new XStream(new JettisonMappedXmlDriver());
xstream.alias("product", Product.class);
Product product = (Product) xstream.fromXML(json);
System.out.println(product.getName());
Prints:
Banana

Using Java ObjectMapper to get JSON String

I am using writeValueAsString of the ObjectMapper . However, it's giving me a Java String representation so I get:
{"network_id":5000370004610700049753}
instead of
"{\"network_id\":5000370004610700049753}"
which is failing for other services when deserializing. How do I get this kind of serialization with the ObjectMapper?

To get the second result, send it through the ObjectMapper again.
Map<String, Object> data = new HashMap<>();
data.put("network_id", new BigInteger("5000370004610700049753"));
ObjectMapper objectMapper = new ObjectMapper();
String plainJson = objectMapper.writeValueAsString(data);
System.out.println(plainJson);
String encodedJson = objectMapper.writeValueAsString(plainJson);
System.out.println(encodedJson);
Output
{"network_id":5000370004610700049753}
"{\"network_id\":5000370004610700049753}"

How to retrieve values from a JSONArray

this is the JSONArray:
String json = [{"1":"Kenny", "2":"Tom", "3":"Mosoti"}];
now i want to get a string array of values only eg Kenny, Tom, Mosoti

You may use any json parser to do that for instance Jackson.
It is not a good option to write your own parser as it is error-prone. Also don't re-invent the wheel.

Yeah, you should go with a mainstream library/framework like Jackson, you can read more about it here: http://wiki.fasterxml.com/JacksonInFiveMinutes
A basic example would be something like:
private static MailData unMarshallJson(String literalJson) throws JAXBException, IOException {
Data data = null;
ObjectMapper mapper = new ObjectMapper();
data = mapper.readValue(literalJson, Data.class);
return data;
}
Where the Data class is a class corresponding to the parsed data, read the link that I provided for more info.