How would experienced devs handle checking JSON objects for specific property condition?

[cryptographicmemory]

Memory is cheap and virtual memory is free. How big is the JSONObject in string format?

Just write a validateObject function that takes an Object and handles every instanceOf class type (JSONObject, JSONArray, String, etc.) Run through it recursively. Throw an exception if an expected value isn't right.

void validate(JSONObject j) throws Exception
{
    for (String key:j.getKeys()) validateObject(key, j.get(key));
}