How to Parse a JSON Object's Values into an ArrayList in Java?

Parsing a JSON Object in Java: Extracting Values into an ArrayList

In this programming scenario, you encounter a JSON object and aim to parse its values into an array list in Java. The JSON object is structured as follows:

{
    "interests": [{
        "interestKey": "Dogs"
    }, {
        "interestKey": "Cats"
    }]
}

To address this task, you can utilize the org.json library. Here's a step-by-step solution:

1. Create a JSON Object: First, you need to construct a JSON object from the given JSON string:

   JSONObject obj = new JSONObject("{interests : [{interestKey:Dogs}, {interestKey:Cats}]}");

2. Retrieve the Interests Array: Next, you need to extract the "interests" array from the JSON object:

   JSONArray array = obj.getJSONArray("interests");

3. Initialize an ArrayList: Now, create an ArrayList to store the interest keys:

   List<String> list = new ArrayList<String>();

4. Iterate Over the Interests Array: Utilize a loop to iterate through the interests array and extract the interest keys:

   for (int i = 0; i < array.length(); i++) {
       list.add(array.getJSONObject(i).getString("interestKey"));
   }

5. Retrieve the Parsed Values: The ArrayList now contains the interest keys from the JSON object:

   System.out.println(list); // Output: [Dogs, Cats]

By following these steps, you can effectively parse the given JSON object in Java and populate an array list with its "interestKey" values.

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