Java 8 Functional Interfaces and Their Use Cases: A Comprehensive Guide for Developers

Java 8 Functional Interfaces and Their Use Cases: A Comprehensive Guide for Developers

1. Consumer Interface

The Consumer interface represents an operation that takes a single input and performs an action on it without returning any result. It’s a perfect choice when we need to consume or perform side effects like logging or modifying objects.

Key Method:

• void accept(T t): Takes a single input parameter of type T and performs some operation on it.

Syntax of the Consumer Interface

@FunctionalInterface
public interface Consumer<T> {
    void accept(T t);
}

Usage Example of the Consumer Interface

Let’s see how to use the Consumer interface with an example.

import java.util.function.Consumer;
public class ConsumerExample {
    public static void main(String[] args) {
        // Creating a Consumer to print the value
        Consumer<String> printConsumer = s -> System.out.println("Consumed value: " + s);
        // Applying the Consumer
        printConsumer.accept("Hello, World!");  // Output: Consumed value: Hello, World!
    }
}

In this example, the Consumer takes a String and simply prints it.