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

If you use complex objects, you should apply enableComplexMapKeySerialization(), as stated in https://stackoverflow.com/a/24635655/2914140 and https://stackoverflow.com/a/26374888/2914140.

Gson gson = new GsonBuilder().enableComplexMapKeySerialization().create();
Map original = new LinkedHashMap();
original.put(new Point(5, 6), "a");
original.put(new Point(8, 8), "b");
System.out.println(gson.toJson(original));

Output will be:

{
 "(5,6)": "a",
 "(8,8)": "b"
}