Java ArrayList getLast() Method (introduced in Java 21)

The ArrayList.getLast() method, introduced in Java 21, is used to retrieve the last element from an ArrayList. This guide will cover the method’s usage, explain how it works, and provide examples to demonstrate its functionality. Additionally, we will cover a real-world use case to illustrate its application.

Table of Contents

1. Introduction
2. getLast Method Syntax
3. How It Works
4. Examples
   • Retrieving the Last Element
   • Handling Empty ArrayList
5. Real-World Use Case
6. Conclusion

Introduction

The ArrayList.getLast() method is part of the ArrayList class in Java 21. It allows you to access the last element of the list directly, simplifying the process of getting the last element without needing to handle the index manually.

getLast Method Syntax

The syntax for the getLast method is as follows:

public E getLast()

• The method returns the last element in the ArrayList.

How It Works

When you use the getLast() method, the ArrayList retrieves the element at the last position (index size() - 1). If the list is empty, the method throws a NoSuchElementException.

Examples

Retrieving the Last Element

The getLast method can be used to retrieve the last element of the ArrayList.

Example

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

public class GetLastExample {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("Apple");
        list.add("Banana");
        list.add("Orange");

        // Retrieve the last element
        String lastElement = ((ArrayList<String>) list).getLast();

        System.out.println("Last element: " + lastElement);
    }
}

Output:

Last element: Orange

Handling Empty ArrayList

Attempting to retrieve the last element from an empty ArrayList will throw a NoSuchElementException. It’s important to handle this case properly.

Example

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

public class GetLastWithExceptionHandling {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();

        // Retrieve the last element with exception handling
        try {
            String lastElement = ((ArrayList<String>) list).getLast();
            System.out.println("Last element: " + lastElement);
        } catch (NoSuchElementException e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}

Output:

Error: No elements found in the list

Real-World Use Case

Accessing the Last Task in a Task List

In a task management system, you might want to access the last task in a list to process or display it. The getLast() method can be used to quickly access the last task.

Example

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

class Task {
    String name;

    Task(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return name;
    }
}

public class TaskList {
    public static void main(String[] args) {
        List<Task> tasks = new ArrayList<>();
        tasks.add(new Task("Write report"));
        tasks.add(new Task("Prepare presentation"));
        tasks.add(new Task("Fix critical bug"));

        // Retrieve the last task
        Task lastTask = ((ArrayList<Task>) tasks).getLast();

        System.out.println("Last task: " + lastTask);
    }
}

Output:

Last task: Fix critical bug

Conclusion

The ArrayList.getLast() method in Java 21 provides a convenient way to retrieve the last element from an ArrayList. By understanding how to use this method, you can efficiently access the last element in your Java applications. It’s important to handle potential NoSuchElementException by ensuring that the list is not empty before attempting to retrieve the last element. This method is particularly useful in real-world applications such as accessing the last task in a task list or retrieving the last item in a collection.