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Parsing JSON string and preserving key-data order when using json-simple without manually constructing HashMap

I know that this topic has been talked about, and the use of a LinkedHashMap is a 'hacky' way to maneuver this, but if I'm given thousands of JSON strings as input, and eventually want to output them back in their original form, is there anyway to preserve the order without manually constructing LinkedHashMaps.
For example a string like this
{"key":1,"surname":"Reed","given":"Ryan","address":{"state":"CA","postal":"90210"},"gender":"M"}
Right now if I parse the object like so:
JSONObject jsonObject = (JSONObject) parser.parse(str);
System.out.println(jsonObject);
My output will look like this:
{"surname":"Reed","gender":M,"address":{"postalCode":"90210","state":"CA"},"key":1,"given":"Ryan"}
Is there anyway I can get the output to match exactly like the given input?

In Json property structure, order does not matter. but if you have specific order in your mind you can use Jackson to order them in you desirable way, both in your server and client apps.
https://www.baeldung.com/jackson
http://www.davismol.net/2016/10/24/jackson-json-using-jsonpropertyorder-annotation-to-define-properties-serialization-order/

I think it is impossible by default.
You can refer to this RFC https://www.ietf.org/rfc/rfc4627.txt
An array is an ordered sequence of zero or more values.
If you want to hack it you can override the data structure and use the data structure which preserves the order.

Spring/Jackson Mapping Inner JSON Objects

I have a RESTful web service that provides JSON that I am consuming. I am using Spring 3.2 and Spring's MappingJacksonHttpMessageConverter. My JSON looks like this:
{
"Daives": {
"Daive": {},
"Daive": {},
"Daive": {},
"Daive": {}
}
}
Now everything I have read seems to indicate that this JSON should be refactored to an array of JSON Daives. However, this is valid JSON so I want to make sure that I am thinking correctly before going back to the service provider to ask for changes. In the format above, I would have to know ahead of time how many Daives there are going to be such that my DTO accounted for them. The handy dandy Jackson mapper isn't going work with this kind of JSON setup. If the JSON was altered to provide and Array of JSON Daives, I could use a List to dynamically map them using Spring/Jackson.
Am I correct? Thanks :)

According to this thread, the JSON spec itself does not forbid multiple fields with the same name (in your case, multiple fields named "Daive" in the object "Daives").
However, most parsers will either return an error or ignore any value but the last one. As you said, putting these values into an array seems much more sensible; and indeed, you'll be able to map this array to a List with Jackson.

How do I print json structure for a multi-level json using java

I am very new to JSON and am not sure if the term "multi-level" json is correct. If not, please help correct it.
I have been tasked with printing the request and response structure of a given rest service. I have the api.json which refers to a host of json objects, which in turn refer to other json objects and so on...
Please note that I am interested in printing the structure and not the contents of the request and response.
I know that I can go ahead and do a recursive read of the files and get this done. But that does not seem right.
Can someone please provide some pointers for the same?

There is a general misconception about JSON. JSON is a format to represent a complex data structure as a string. That's it. JSON itself doesn't know anything about structure - it's really just a string. What you can do is parse the JSON string to get JavaScript objects (i.e. numbers, strings, arrays and things of type object).
This means that you can't really learn enough about the structure of the rest service by looking at JSON strings it accepts or sends. You need to look at the documentation or the internal objects which the service uses to parse the JSON instead.
Example:
{"foo":"bar"}
That tells you that the REST service accepts a JavaScript object and one of the possible parameters. But it doesn't tell you about the other 50 parameters.
If you only have the JSON, then you can use a parsing library to turn that into something that you can print. But unless you want pretty printing (indent and such), that's the same as printing the JSON string itself, so you don't gain anything.

Converter from Json into groovy CODE?

It's a kind of odd question for an odd situation. I have a large JSON structure which I would like to represent in running groovy code. I need groovy objects that mirror the same structure as the JSON objects.
As to be expected a web search mostly returns results with groovy/json runtime conversion stuff, but nothing about things that output groovy code.
You might think this lazy but really it is a massive JSON structure! A converter would save days!

You can use Groovy's own JsonSlurper to parse JSON objects:
import groovy.json.*
def json = '{"name":"john", "surname":"doe", "languages": ["groovy", "python"]}'
def obj = new JsonSlurper().parseText(json)
assert obj.name == "john"
assert obj.surname == "doe"
assert obj.languages.containsAll("python", "groovy")
Of course the class is untyped: it's only known at runtime. If you want it to be typed, you can write a code which writes the code based on an example (since a json schema may be rare).
EDIT: if you want to generate the model classes code, you can try JSONGen, which "parses JSON to create client side source files to model the JSON data structure". I'm not aware of a solution for Groovy, but since java-groovy integrations is seamless, it shall work fine.

If you want a Groovy representation of your JSON, you can get that via the built-in JsonSlurper. This will give you Java Maps and Lists of data you can work with.
You can populate more specific, custom objects you've written to represent your JSON entities using the (3rd party) Jackson's data binding functionality (see this question as well).

Try using a JSON parser like this one. According to its documentation you just need to do
JSON.parse
to deserialize the data

Mustache kind of String replacement in Java

My application allows users to define few templates for text etc. Eg: one of the shortcuts could be hi {{name}}, nice to meet you.
I have a complex json which has name and lot of inner jsons. I am looking for a good mustache kind of implementation in java which can replace the values of json into the string. Currently I am iterating through each key and replacing the string but I am looking for more elegant solution which gives the users more power in their templating like loops, conditions etc similar to mustache/handlebars.
Though mustache for java looks good, I haven't seen any implementation which can replace with a JSON. All examples applies on an object but not on a json object. Looks to me that internally, it uses an object mapper to convert an object to object and somehow it applies that.
Perhaps I can convert JSON into a map and provide it.
Probably I am missing something. Thanks.

You have to convert the JSON string to a Java object. You can use a nested Map, Multimap or create you own object to represent the structure.
You probably want to use a JSON-serializer to create a java object from the JSON-string. Good solutions are Jackson, Gson or Json-simple.
Once you have a correct Java representation of the JSON, you can use a template engine to do the string replacement. Known libraries are Freemarker, Velocity and StringTemplate
Personally I recommend Jackson+Freemarker, but all are good solutions.

Try Apache Velocity it does something very similar for property substitution in text.

Chunk is a very JSON-friendly template engine. Loops & conditions, tag syntax is similar to Mustache, and you can reference nested associative arrays of data fairly elegantly right from the template.
See sample code for JSON + Chunk in this answer.