👀 Views: 94 💬 Answers: 1 📅 Created: 2025-06-06

java optional streams filter Java

I'm working with an unexpected behavior when using `Optional` in conjunction with Java Streams while filtering a list of custom objects. I have a class `User` with a field `age`, and I'm trying to filter users who are above a certain age and then retrieve the first one using `Optional`. Here's a simplified version of my code: ```java import java.util.Arrays; import java.util.List; import java.util.Optional; class User { private String name; private int age; public User(String name, int age) { this.name = name; this.age = age; } public int getAge() { return age; } } public class UserFilter { public static void main(String[] args) { List<User> users = Arrays.asList(new User("Alice", 25), new User("Bob", 20), new User("Charlie", 30)); int ageLimit = 22; Optional<User> userOptional = users.stream() .filter(user -> user.getAge() > ageLimit) .findFirst(); userOptional.ifPresent(user -> System.out.println(user.getName())); } } ``` When I run this, I expect to see "Alice" printed because she is the first user above 22, but it prints nothing. I double-checked that my age limit is set correctly and that the list contains users who should pass the filter. I also tried printing the `users` list before filtering to confirm the contents: ```java users.forEach(user -> System.out.println(user.getName() + " - Age: " + user.getAge())); ``` This correctly outputs: - Alice - Age: 25 - Bob - Age: 20 - Charlie - Age: 30 So the users are indeed there, but for some reason, the filter seems to be returning no results. I also attempted to debug by replacing the filter with a simple condition like `user -> true`, and it worked as expected, returning the first user. Can anyone explain why the filter condition is not working as intended? Is there a known scenario with `Optional` and Streams in Java 15 that I'm not aware of? I'm using Java 3.9 in this project. How would you solve this?