👀 Views: 39 💬 Answers: 1 📅 Created: 2025-06-10

java stream exception Java

I need help solving I've looked through the documentation and I'm still confused about I'm trying to figure out I'm working with a `ClassCastException` when trying to sort a list of custom objects using the Stream API in Java 17... I have a class `Person` with fields `name` (String) and `age` (int). I'm attempting to sort a list of `Person` objects by age in descending order using a custom comparator. Here's the code I'm currently using: ```java import java.util.*; import java.util.stream.*; class Person { String name; int age; Person(String name, int age) { this.name = name; this.age = age; } } public class Main { public static void main(String[] args) { List<Person> people = Arrays.asList( new Person("Alice", 30), new Person("Bob", 25), new Person("Charlie", 35) ); List<Person> sortedPeople = people.stream() .sorted(Comparator.comparingInt(Person::getAge).reversed()) .collect(Collectors.toList()); sortedPeople.forEach(person -> System.out.println(person.name + " - " + person.age)); } } ``` When I run this code, I get the following behavior: ``` Exception in thread "main" java.lang.ClassCastException: java.lang.Integer want to be cast to java.lang.String at java.base/java.util.Comparator.naturalOrder(Comparator.java:107) at java.base/java.util.Comparator.comparingInt(Comparator.java:104) ``` I've verified that the `getAge()` method returns an int, but I'm puzzled as to why I'm seeing a `ClassCastException`. Is there something I'm missing in the way I'm using the comparator? I've also tried simplifying the comparator to just `Comparator.reverseOrder()` but it didn't resolve the scenario. Any insights or suggestions on how to solve this would be appreciated! The stack includes Java and several other technologies. This is for a REST API running on Windows 10. Thanks for taking the time to read this! Thanks for your help in advance!