¿Cómo funciona un iterador en Java?

How does an iterator work in Java?

‘ListIterator’ in Java is an Iterator which allows users to traverse Collection in both direction. It contains the following methods: void add(Object object): It inserts object immediately before the element that is returned by the next( ) function. boolean hasNext( ): It returns true if the list has a next element.

Java provides Iterator and ListIterator classes to retrieve the elements of the collection object.

1. The hasNext() method of these interfaces returns true if the collection object has next element else it returns false.
2. The next() methods of the Iterator and ListIterator returns the next element of the collection.

The order in which the elements contained in a Java Iterator are traversed depends on the object that supplies the Iterator . For instance, an iterator obtained from a List will iterate through the elements of that List in the same order the elements are stored internally in the List .

hasNext() : hasNext() method returns true if iterator have more elements. next() : next() method returns the next element and also moves cursor pointer to the next element. hasNext() – Returns true if the iteration has more elements. next() – Returns the next element in the iteration.

The hasNext() method checks if the Scanner has another token in its input. A Scanner breaks its input into tokens using a delimiter pattern, which matches whitespace by default. That is, hasNext() checks the input and returns true if it has another non-whitespace character.

If there is an element after where hasNext () has returned false on which some execution is to be performed then this method is used to display that element on which execution is supposed to be carried on with help of this method. The next () methods of the Iterator and List Iterator returns the next element of the collection.

The hasNext () methods of the Iterator and List Iterator returns true if the collection object over which is used to check during traversal whether the pointing element has the next element. If not it simply returns false. So,

The hasNext() is a method of Java Scanner class which returns true if this scanner has another token in its input. There are three different types of Java Scanner hasNext() method which can be differentiated depending on its parameter. These are: Java Scanner hasNext () Method. Java Scanner hasNext (String pattern) Method.

To use an Iterator, you must import it from the java.util package. The iterator () method can be used to get an Iterator for any collection: To loop through a collection, use the hasNext () and next () methods of the Iterator: Iterators are designed to easily change the collections that they loop through.