How to Include Null Values in a JSON Object When Making API Calls?

Why are null values not included in my JSON object when making API calls?

JSONObject params = new JSONObject();
params.put(KEY_TOKEN, token); // token is null
params.put(KEY_DATE, date); // date has a valid value
Log.e("params ", params+"");

When building a JSON object in Java and attempting to include an uninitialized variable, such as a null value, the null values are often omitted from the resulting JSON. This can lead to incomplete data being sent in API requests. This behavior is consistent across many JSON libraries, where null values do not get serialized into the output JSON string, unlike defined values which are well attached to their respective keys.

String token = null; // Example of an uninitialized variable
JSONObject params = new JSONObject();
params.put(KEY_TOKEN, token); // This will be ignored in JSON output
params.put(KEY_DATE, date);
Log.e("params ", params.toString()); // Output will exclude token if it's null.

Causes

• The variable `token` is declared but not initialized, resulting in its value being null.
• When you add an entry to the JSON object where the value is null, it does not appear in the serialized JSON output.
• JSON libraries typically ignore null values to keep the object clean and avoid confusion.

Solutions

• Explicitly set a default value for your variable if it is possible, such as an empty string, if applicable.
• Check if the variable is null before adding it to the JSON object and handle it accordingly based on your application context, e.g., params.put(KEY_TOKEN, token != null ? token : "default_token").
• If you need to explicitly include null values in your JSON, consider using a custom serialization approach that includes nulls.

Mistake: Assuming the JSON object automatically includes null values.

Solution: Understand that by design, JSON objects exclude null values, so always initialize your variables or handle nulls before adding them.

Mistake: Overlooking the variable scope and initialization before the JSON object creation.

Solution: Ensure that all variables are properly initialized with a fallback value if they might be null.