11 November 2019

Java Loop Through List

development

In this tutorial, we look at five different ways we can iterate through an ArrayList in Java. As of Java 8, we can use the forEach method as well as the iterator class to loop over an ArrayList.

Looping over an ArrayList

There are primarily 5 different ways to loop over an ArrayList

Classic For Loop
Advanced For Loop
Iterator
While Loop
ForEach (Java 8)

First, let’s create an ArrayList to use in the loop examples:

import java.util.ArrayList;
import java.util.List;

public class LoopOverArrayExamples {

    private List fruitBasket = new ArrayList<>(0);

    public void addFruitsToBasket() {
        fruitBasket.add("Apple");
        fruitBasket.add("Banana");
        fruitBasket.add("Pear");
        fruitBasket.add("Mango");
    }
}

Using Classic For Loop

for (int i=0; i<fruitBasket.size(); i++) {
    System.out.println(fruitBasket.get(i));
}

Advanced For Loop

for(String fruit : fruitBasket) {
    System.out.println(fruit);
}

Using Iterator

Iterator fruitIterator = fruitBasket.iterator();
while (fruitIterator.hasNext()) {
    System.out.println(fruitIterator.next());
}

Using While Loop

int i = 0;
while (i < fruitBasket.size()) {
    System.out.println(fruitBasket.get(i));
    i++;
}

ForEach (Java 8)

fruitBasket.forEach( (fruit) ->
    System.out.println(fruit)
);

11 November 2019