Java LinkedHashSet getLast() Method (Introduced in Java 21)

In Java 21, the LinkedHashSet class introduced the getLast() method, allowing you to retrieve the last element of the collection.

Table of Contents

1. Introduction
2. getLast Method Syntax
3. Examples
   • Retrieving the Last Element in LinkedHashSet
   • Handling an Empty LinkedHashSet
4. Real-World Use Case
   • Use Case: Task Management System
5. Conclusion

Introduction

The LinkedHashSet.getLast() method is a new addition in Java 21 that allows you to retrieve the last element of the LinkedHashSet. This method is useful when you need to access the last element of the collection while maintaining the order of insertion.

getLast() Method Syntax

The syntax for the getLast method is as follows:

public E getLast()

• The method does not take any parameters.
• The method returns the last element of the LinkedHashSet.

Examples

Retrieving the Last Element in LinkedHashSet

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

Example

import java.util.LinkedHashSet;

public class GetLastExample {
    public static void main(String[] args) {
        // Creating a LinkedHashSet of Strings
        LinkedHashSet<String> animals = new LinkedHashSet<>();

        // Adding elements to the LinkedHashSet
        animals.add("Lion");
        animals.add("Tiger");
        animals.add("Elephant");

        // Retrieving the last element
        String lastAnimal = animals.getLast();

        // Printing the last element
        System.out.println("Last animal: " + lastAnimal);
    }
}

Output:

Last animal: Elephant

Handling an Empty LinkedHashSet

When the LinkedHashSet is empty, calling getLast will result in an exception. Therefore, it's important to check if the set is empty before calling this method.

Example

import java.util.LinkedHashSet;

public class GetLastEmptyExample {
    public static void main(String[] args) {
        // Creating an empty LinkedHashSet of Strings
        LinkedHashSet<String> animals = new LinkedHashSet<>();

        // Checking if the LinkedHashSet is empty before retrieving the last element
        if (!animals.isEmpty()) {
            String lastAnimal = animals.getLast();
            System.out.println("Last animal: " + lastAnimal);
        } else {
            System.out.println("The LinkedHashSet is empty.");
        }
    }
}

Output:

The LinkedHashSet is empty.

Real-World Use Case

Use Case: Task Management System

In a task management system, tasks are often managed in the order they are added. There are scenarios where the last task needs to be retrieved for review or processing. The getLast method can be used to achieve this functionality.

Example

import java.util.LinkedHashSet;

public class TaskManagementSystem {
    public static void main(String[] args) {
        // Creating a LinkedHashSet to store tasks
        LinkedHashSet<String> tasks = new LinkedHashSet<>();

        // Adding initial tasks
        tasks.add("Complete project report");
        tasks.add("Email client updates");
        tasks.add("Prepare presentation");

        // Retrieving the last task
        if (!tasks.isEmpty()) {
            String lastTask = tasks.getLast();
            System.out.println("Last task to be reviewed: " + lastTask);
        } else {
            System.out.println("No tasks available.");
        }
    }
}

Output:

Last task to be reviewed: Prepare presentation

Conclusion

The LinkedHashSet.getLast() method introduced in Java 21 provides a way to retrieve the last element of a LinkedHashSet. By understanding how to use this method, you can efficiently access the last element while maintaining the order of elements in your collections. This method is useful for accessing the last inserted element in a predictable manner, making it a valuable tool for collection management in your Java applications. The real-world use case of a task management system illustrates the practical application of this method in retrieving tasks for review or processing.