Unexpected Behavior with Java Stream API - Filtering and Collecting into Map
I can't seem to get I'm relatively new to this, so bear with me... I'm experiencing unexpected behavior when using the Java Stream API to filter a list of objects and collect the results into a map. I'm working with Java 11 and have a list of `Person` objects, where each person has a `name` and an `age`. I want to create a map where the key is the person's name and the value is their age, but my code returns an empty map instead of the expected results. Here’s the code snippet I’m using: ```java import java.util.List; import java.util.Map; import java.util.stream.Collectors; public class Main { public static void main(String[] args) { List<Person> people = List.of( new Person("Alice", 30), new Person("Bob", 25), new Person("Charlie", 35) ); Map<String, Integer> nameToAge = people.stream() .filter(person -> person.getAge() > 30) .collect(Collectors.toMap(Person::getName, Person::getAge)); System.out.println(nameToAge); } } class Person { private String name; private int age; public Person(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public int getAge() { return age; } } ``` When I run this code, the output is an empty map: `{}`. I expected to see the entries for `Charlie`, but since the age filter is `> 30`, it seems like it should work. I’ve tried debugging by printing each person in the filter step, and they all seem to have the correct values. Also, I tried changing the filter condition to `>= 30`, but it still returns an empty map. I've also checked the documentation to ensure I'm using `Collectors.toMap` correctly, but I can’t find what I might be missing. Is there something subtle I might have overlooked in my filtering or collecting logic? Any help would be greatly appreciated! My development environment is Linux. I'd really appreciate any guidance on this. I recently upgraded to Java LTS. Any feedback is welcome!