The org.json based classes included in Android don't have any features related to converting Java POJOs to/from JSON.

If you have a list of some class (List<GroupItem>) and you absolutely need to convert that to a org.json.JSONArray you have two choices:

A) Use Gson or Jackson to convert to JSON, then parse that JSON into a JSONArray:

List<GroupItem> list = ...
String json = new Gson().toJson(list);
JSONArray array = new JSONArray(json);

B) Write code to create the JSONArray and the JSONObjects it will contain from your Java objects:

JSONArray array = new JSONArray();
for (GroupItem gi : list)
{
    JSONObject obj = new JSONObject();
    obj.put("fieldName", gi.fieldName);
    obj.put("fieldName2", gi.fieldName2);
    array.put(obj);
}

Check out the Gson API and some examples. I've put the links below!

String jsonString = //your json String
Gson gson = new Gson();
Type typeOfList = new TypeToken<List<Map<String, Integer>>>() {}.getType();
List<Map<String, Integer>> list = gson.fromJson(jsonString, typeOfMap);

List<Click> clicks = new ArrayList<Click>();
for(int i = 0; i < list.size(); i++) {
    int x = list.get(i).get("x");
    int y = list.get(i).get("y");
    clicks.add(new Click(x, y));
}

(http://google-gson.googlecode.com/svn/trunk/gson/docs/javadocs/com/google/gson/Gson.html) (http://google-gson.googlecode.com/svn/tags/1.5/src/test/java/com/google/gson/functional/MapTest.java)

It works for me.

JSONObject obj = new JSONObject(result.toString());
JSONArray arr = obj.getJSONArray("value");

I know this is old (and I am new to java), but I ran into the same problem. And the answers were not as clear to me as a newbie... so I thought I would add what I learned.

I used a third-party library to aid in the endeavor: org.codehaus.jackson All of the downloads for this can be found here.

For base JSON functionality, you need to add the following jars to your project's libraries: jackson-mapper-asl and jackson-core-asl

Choose the version your project needs. (Typically you can go with the latest stable build).

Once they are imported in to your project's libraries, add the following import lines to your code:

 import org.codehaus.jackson.JsonGenerationException;
 import org.codehaus.jackson.map.JsonMappingException;
 import com.fasterxml.jackson.databind.ObjectMapper;

With the java object defined and assigned values that you wish to convert to JSON and return as part of a RESTful web service

User u = new User();
u.firstName = "Sample";
u.lastName = "User";
u.email = "sampleU@example.com";

ObjectMapper mapper = new ObjectMapper();
    
try {
    // convert user object to json string and return it 
    return mapper.writeValueAsString(u);
}
catch (JsonGenerationException | JsonMappingException  e) {
    // catch various errors
    e.printStackTrace();
}

The result should looks like this: {"firstName":"Sample","lastName":"User","email":"sampleU@example.com"}

Even shorter and with json-functions:

JSONObject songsObject = json.getJSONObject("songs");
JSONArray songsArray = songsObject.toJSONArray(songsObject.names());

ArrayList<String> list = new ArrayList<String>();
list.add("blah");
list.add("bleh");
JSONArray jsArray = new JSONArray(list);

This is only an example using a string arraylist