Use below code to find key is exist or not in JsonObject. has("key") method is used to find keys in JsonObject.
containerObject = new JSONObject(container);
//has method
if (containerObject.has("video")) {
//get Value of video
String video = containerObject.optString("video");
}
If you are using optString("key") method to get String value then don't worry about keys are existing or not in the JsonObject.