How to convert hashmap to JSON object in Java

Question

How to convert or cast hashmap to JSON object in Java, and again convert JSON object to JSON string?

Answer 1

First convert all your objects into valid Strings

HashMap params = new HashMap<>();
params.put("arg1", "some text");
params.put("arg2", someObject.toString());

Then insert the entire map into a org.json.JSONObject

JSONObject postData = new JSONObject(params);

Now you can get the JSON by simply calling the object's toString

postData.toString()
//{"arg1":"some text<\/b>" "arg2":"object output"}

Create a new JSONObject

JSONObject o = new JSONObject(postData.toString());

Or as a byte array for sending over HTTP

postData.toString().getBytes("UTF-8");