Confusion with Stable Sort When Ordering Events by Timestamp in Java 11
I keep running into I'm experimenting with I've been researching this but I'm relatively new to this, so bear with me. I'm stuck on something that should probably be simple. I'm having trouble with sorting a list of event objects by their timestamps using Java's `Collections.sort()` method. The requirement is to maintain the order of events that have the same timestamp, but it seems that the current implementation isn't achieving this. Here's the code snippet I'm using: ```java import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; class Event { String name; long timestamp; Event(String name, long timestamp) { this.name = name; this.timestamp = timestamp; } } public class EventSorter { public static void main(String[] args) { List<Event> events = new ArrayList<>(); events.add(new Event("Event1", 1620000000)); events.add(new Event("Event2", 1620000001)); events.add(new Event("Event3", 1620000000)); events.add(new Event("Event4", 1620000002)); Collections.sort(events, new Comparator<Event>() { @Override public int compare(Event e1, Event e2) { return Long.compare(e1.timestamp, e2.timestamp); } }); for (Event event : events) { System.out.println(event.name + " - " + event.timestamp); } } } ``` When I run this code, the output is sorted by timestamp, but I'm noticing that `Event1` and `Event3`, which have the same timestamp, do not retain their original order in the output. This is problematic because I need to ensure that events with identical timestamps are presented in the order they were added to the list. I read that `Collections.sort()` should be stable, but I suspect something in my implementation is going wrong. I've also tried using `List.sort()` with a lambda expression, but that didn't change the outcome. Is there something Iām missing, or perhaps another way to ensure stable sorting in Java 11? Any insights would be greatly appreciated. My development environment is Windows. For context: I'm using Java on Ubuntu. My team is using Java for this desktop app. This issue appeared after updating to Java 3.10. Has anyone dealt with something similar? My team is using Java for this CLI tool.