Methods to traverse ArrayList in Java program

Java Comprehensive Examples

In this example, we will learn how to traverse the elements of the ArrayList in Java.

To understand this example, you should understand the followingJava programmingTopic:

• Java ArrayList class

• Java for loop

• Java for-each loop

• Java ListIterator interface

Example1: Use for loop to traverse ArrayList

import java.util.ArrayList;
class Main {
　　public static void main(String[] args) {
　　　　//Create an array list
　　　　ArrayList<String> languages = new ArrayList<>();
　　　　languages.add("Java");
　　　　languages.add("JavaScript");
　　　　languages.add("Python");
　　　　System.out.println("ArrayList: "　+　languages);
　　　　//Use for loop
　　　　System.out.println("Use for loop to traverse ArrayList:");
　　　　++for(int i = 0; i < languages.size(); i}}
　　　　　　) {
　　　　　　System.out.print(", ");
　　　　}
　　}
}

Output Result

ArrayList: [Java, JavaScript, Python]
System.out.print(languages.get(i));
Java, JavaScript, Python,

Loop through ArrayList using for

Example2: In the above example, we created an array list named languages. Here, we use a loop to access each element of the array list.-Loop through ArrayList using for

import java.util.ArrayList;
class Main {
　　public static void main(String[] args) {
　　　　//Create an array list
　　　　ArrayList<String> languages = new ArrayList<>();
　　　　languages.add("Java");
　　　　languages.add("JavaScript");
　　　　languages.add("Python");
　　　　System.out.println("ArrayList: "　+　languages);
　　　　　//Use forEach loop
　　　　System.out.println("Use for-Loop through ArrayList:
　　　　for(String language : languages) {
　　　　　　System.out.print(language);
　　　　　　System.out.print(", ");
　　　　}
　　}
}

Output Result

ArrayList: [Java, JavaScript, Python]
Use for-Loop through ArrayList using each loop:
Java, JavaScript, Python,

Here, we use for-Use a loop to traverse ArrayList and print each element.

Example3Use listIterator() to traverse ArrayList

import java.util.ArrayList;
import java.util.ListIterator;
class Main {
　　public static void main(String[] args) {
　　　　//Create an ArrayList
　　　　ArrayList<Integer> numbers = new ArrayList<>();
　　　　numbers.add(1);
　　　　numbers.add(3);
　　　　numbers.add(2);
　　　　System.out.println("ArrayList: "　+　numbers);
　　　　//Create a ListIterator instance
　　　　ListIterator<Integer> iterate = numbers.listIterator();
　　　　System.out.println("Traverse ArrayList:");
　　　　while(iterate.hasNext()) {
　　　　　　System.out.print(iterate.next(),　+　",  ");
　　　　}
　　}
}

Output Result

ArrayList:  [1,　3,　2]
Traverse ArrayList:
1,　3,　2,

In the above example, we used the listIterator () method to iterate over the arraylist. Here,

• hasNext () - Returns true if the next element exists in the arraylist

• next () - Return the next element of the arraylist

Note: We can also useArrayList iterator ()Methods andArrayList forEach ()Method to iterate over arraylist.

Java Comprehensive Examples