An Iterator is an object that can be used to loop through collections, like ArrayList and HashSet. It is called an "iterator" because "iterating" is the technical term for looping. To use an Iterator, you must import it from the java. util package.
The primary purpose of an iterator is to allow a user to process every element of a container while isolating the user from the internal structure of the container. This allows the container to store elements in any manner it wishes while allowing the user to treat it as if it were a simple sequence or list.
Java Iterator Interface of java collections allows us to access elements of the collection and is used to iterate over the elements in the collection(Map, List or Set). It helps to easily retrieve the elements of a collection and perform operations on each element.
Iterable is an object, which one can iterate over. ... Iterator is an object, which is used to iterate over an iterable object using __next__() method. Iterators have __next__() method, which returns the next item of the object. Note that every iterator is also an iterable, but not every iterable is an iterator.
Iterators are used to traverse through the Java collections. There are three types of iterators.
Iterator enables you to cycle through a collection, obtaining or removing elements. ... Each of the collection classes provides an iterator( ) method that returns an iterator to the start of the collection. By using this iterator object, you can access each element in the collection, one element at a time.
To implement an Iterator, we need a cursor or pointer to keep track of which element we currently are on. Depending on the underlying data structure, we can progress from one element to another. This is done in the next() method which returns the current element and the cursor advances to next element.
