I'm trying to create a system that syncs entities and extended entity properties automatically. However, sometimes the first one or two entities it tries to sync return null when attempting to obtain them via getEntityByID, upon beginning a new world. This probably has something to do with threading, however I'm performing the sync at the EntityJoinWorldEvent, and according to the console, this IS being executed in the correct thread (the server logs "Error executing task" before the exception is thrown). So, what am I missing?

EntityJoinWorldEvent fires on the server before the entity even exists on the client. So that is not going to work.

Use PlayerEvent.StartTracking to get notified when a player starts "seeing" an entity.

 

Ah, thanks, I thought I might have subscribed to the wrong event. This fires for the player themselves as well, right?

I am not sure actually. It definitely fires for other players, but you might have to use PlayerLoggedInEvent as well, if it does not fire for the player themselves.

 

Ok thank you, I'll try this out then.

Ok, I just finished implementing it, and it works. You were right that the PlayerEvent.StartTracking event doesn't fire on the player themselves, but you were also right that PlayerLoggedInEvent was also an acceptable substitute. Thanks.