Primitive Function Interfaces in Java: IntFunction, LongFunction, and DoubleFunction

1. Introduction to Primitive Functional Interfaces

Hello everyone, welcome back! In this blog post, we’re going to discuss three important primitive Function functional interfaces in Java: IntFunction, LongFunction, and DoubleFunction. These interfaces allow us to operate on primitive types (int, long, double) without the performance overhead caused by autoboxing. We’ll go over what autoboxing is and why it’s important to avoid it in performance-critical applications. Let’s get started!

Read this article for free on my blog: IntFunction, LongFunction, and DoubleFunction in Java.

2. What is Autoboxing?

Before we dive into these primitive functional interfaces, let’s briefly discuss autoboxing. Autoboxing is the automatic conversion of primitive types like int, long, and double into their respective wrapper classes: Integer, Long, and Double. While this automatic conversion is convenient, it adds overhead because every primitive value has to be wrapped into an object, consuming more memory and processing time.

2.1 Example: Autoboxing with Function<Integer, String>

import java.util.function.Function;

public class AutoboxingExample {

    public static void main(String[] args) {
        // Function<Integer, String> causes autoboxing
        Function<Integer…