Introducing the forEachRemaining() in Iterator.

This lesson explains the forEachRemaining() method, which was introduced in the iterator class in Java 8.

We'll cover the following

forEachRemaining() in Iterator

Iterator is an interface available in the Collections framework in java.util package. It is used to iterate a collection of objects. This interface has four methods, as shown in the below image. Before, Java 8 the forEachRemaining() method did not exist.

widget

Below is a simple program to iterate a list using iterator before Java 8.

Press + to interact
import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;



public class IteratorDemo {



    public static void main(String args[]) {



        List<String> fruits = new ArrayList<>();

        fruits.add("Apple");

        fruits.add("Banana");

        fruits.add("Grapes");

        fruits.add("Orange");



        Iterator<String> iterator = fruits.iterator();



        while (iterator.hasNext()) {

            System.out.println(iterator.next());

        }

    }

}

As you can see in the above example requires a while loop in order to iterate through the input list via an Iterator. To avoid this, the forEachRemaining() method was introduced in Java 8. This method takes in a Consumer instance as a parameter.

As you have seen in the Consumer interface lesson that it taken in a parameter and does not return anything. This is what we require for our iterator. Below is the same example shown above, but, this time, we are using the forEachRemaining() method.

Press + to interact
import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;



public class IteratorDemo {



    public static void main(String args[]) {



        List<String> fruits = new ArrayList<>();

        fruits.add("Apple");

        fruits.add("Banana");

        fruits.add("Grapes");

        fruits.add("Orange");



        Iterator<String> iterator = fruits.iterator();



        iterator.forEachRemaining((fruit) -> System.out.println(fruit));

    }

}

Therefore, the main purpose of introducing the forEachRemaining() method was to make the iteration code more concise and readable.

In the next lesson, we will discuss improvements in Map API.

Get hands-on with 1300+ tech skills courses.