What is xib in iOS?

What is difference between Exception and Error in iOS?.

what is dispatchQueue?

what is push notification in ios?

what is major difference between delegate and notification?

What is bundle , document directory and sandbox ?

What is UICollectionView?

What is UITableView?

What is Automatic Reference Counting (ARC) ?

What is Category ?

What is IBOutlet in iOS?

What is Core Data?