import org.json.JSONObject;

public static void printJsonObject(JSONObject jsonObj) {
    jsonObj.keySet().forEach(keyStr ->
    {
        Object keyvalue = jsonObj.get(keyStr);
        System.out.println("key: "+ keyStr + " value: " + keyvalue);

        //for nested objects iteration if required
        //if (keyvalue instanceof JSONObject)
        //    printJsonObject((JSONObject)keyvalue);
    });
}