Java Optional Class: Eliminating NullPointerExceptions Gracefully

Sir Tony Hoare famously called the invention of the null pointer his "billion-dollar mistake". In Java, NullPointerException (NPE) has historically been the #1 cause of production application crashes. java.util.Optional<T> provides an elegant, expressive container to eliminate null checks.

Creating and Consuming Optional Objects

import java.util.Optional;

public class OptionalDemo {
    // Method explicitly declares that a User might not exist!
    public static Optional<String> findUserEmail(int userId) {
        if (userId == 101) {
            return Optional.of("aarav@veewom.com"); // Non-null container
        }
        return Optional.empty(); // Safe empty container (No null returned!)
    }

    public static void main(String[] args) {
        Optional<String> userEmail = findUserEmail(101);

        // 1. ifPresent() - Executes Consumer only if value exists
        userEmail.ifPresent(email -> System.out.println("Sending alert to: " + email));

        // 2. orElse() - Fallback default value
        Optional<String> unknownEmail = findUserEmail(999);
        String finalEmail = unknownEmail.orElse("support@veewom.com");
        System.out.println("Target: " + finalEmail); // support@veewom.com

        // 3. orElseThrow() - Throws custom business exception if absent
        String verified = userEmail.orElseThrow(() -> new RuntimeException("User not found!"));
    }
}