getJSON vs. optJSON

A value in the JSON may be optional, so using optJSONObject is better because you just have to check if it is null or not and continue your function.

optString returns the empty string ("") if the key you specify doesn't exist. getString throws a JSONException.

1. Yes. getJSONObject() throws an exception when that object is not found. optJSONObject() returns null.
2. Honestly there aren't really any advantages to one over the other, it's really a matter of personal preference.
3. Only reason I can think of is for readability potentionally. For instance see how this code accomplishes the same thing

This option is a bit easier to read if you are doing a lot more when the object isn't present.

JSONObject object = jsonResponse.optJSONObject("object");if(object == null){    // handle not existing here}

This option is a bit easier if you are only throwing another exception or doing something else that's one line.

JSONObject object = null;    try{    object = jsonResponse.getJSONObject("object");}catch(JSONException je){    // handle object not found here}