What is the effect of using 'weak' in the following @property definition: @property (nonatomic, weak) SomeClass *responder; ?

Which scenario will not result in NSOperation throwing an exceptions:

In Objective C, all instance methods are accessors.

What class can implement Document Objects?

Which method is used to deallocate all the noncritical custom data structure associated with your view controller?

How can an application respond to they keyboard being dismissed by the user

Which is an object that manages a memory—based data buffer in Grand Central Dispatch (GCD)?

Which classes manages notif‌ication-related activities for an app or app extension?

Which ApplePay JS Data Types showcases the outcome of authorizing a payment request and contains encrypted payment information?

Which Messages framework classes is used to display a dynamically-generated list of stickers. which is capable of drag-and-drop functionality?

Which classes handles the editable content of a notification?