Error when using JSONSimple to write a json file with for loop

Question

I need to transform my data in a ArrayList to a JSON file, and I use JSON.simple. Everything is fine except one little thing that I want to get a result like ...... {source:0, target:1},{source:0, target:1},{source:0, target:2},{source:0, target:3} ...... but it returns ......{source:0, target:16},{source:0, target:16},{source:0, target:16}...... . My solution.size() is 17. Here is my code:

        JSONObject jsonObject = new JSONObject();
        JSONObject jsonNodesObject = new JSONObject();
        JSONObject jsonEdgesObject = new JSONObject();
        JSONArray jsonNodesArray = new JSONArray();
        JSONArray jsonEdgesArray = new JSONArray();

        String instString = solutions.get(0).get("institution");
        jsonNodesObject.put("name", instString);
        // extract name and institution from ArrayList
        for (int i = 0; i < solutions.size(); i++)
        {
            HashMap<String, String> eleHashMap= solutions.get(i);
            String nameString = eleHashMap.get("name");
            jsonNodesObject.put("name", nameString);
            jsonNodesArray.add(jsonNodesObject);
            jsonEdgesObject.put("source", 0);
            jsonEdgesObject.put("target", i);
            jsonEdgesArray.add(jsonEdgesObject);
        }
        jsonObject.put("nodes", jsonNodesArray);
        jsonObject.put("edges", jsonEdgesArray);
        System.out.println(jsonObject);

It seems that in every for loop, it refreshes the value of target: i of all my jsonEdgesArray.

Dose anyone know how to fix this? Thanks in advance!

Answer 1

As your iterating jsonNodesObject in for loop, same value will be put for jsonNodesObject.put("name", nameString); u have to initialize JSONObject jsonNodesObject = new JSONObject(); inside for loop