Which design pattern Iterator follows?

It follows Iterator design pattern. Iterator Pattern is a type of behavioral pattern. The Iterator pattern is one, which allows you to navigate through a collection of data using a common interface without knowing about the underlying implementation. Iterator should be implemented as an interface. This allows the user to implement it anyway its easier for him/her to return data. The benefits of Iterator are about their strength to provide a common interface for iterating through collections without bothering about underlying implementation. Example of Iteration design pattern - Enumeration The class java.util.Enumeration is an example of the Iterator pattern. It represents and abstract means of iterating over a collection of elements in some sequential order without the client having to know the representation of the collection being iterated over. It can be used to provide a uniform interface for traversing collections of all kinds.