ConcurrentModificationException in XUChunkLoaderManager.reloadChunkLoaders

[Sainan]

Had this cause a crash on a modded 1.12 server:

[18:10:34] [Server thread/ERROR] [net.minecraft.server.MinecraftServer]: Encountered an unexpected exception
java.util.ConcurrentModificationException: null
	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1445) ~[?:1.8.0_272]
	at java.util.HashMap$ValueIterator.next(HashMap.java:1474) ~[?:1.8.0_272]
	at com.rwtema.extrautils2.chunkloading.XUChunkLoaderManager.reloadChunkLoaders(XUChunkLoaderManager.java:108) ~[XUChunkLoaderManager.class:?]
	at com.rwtema.extrautils2.chunkloading.XUChunkLoaderManager.serverTick(XUChunkLoaderManager.java:71) ~[XUChunkLoaderManager.class:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_217_XUChunkLoaderManager_serverTick_ServerTickEvent.invoke(.dynamic) ~[?:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) ~[ASMEventHandler.class:?]
	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182) ~[EventBus.class:?]
	at net.minecraftforge.fml.common.FMLCommonHandler.onPreServerTick(FMLCommonHandler.java:279) ~[FMLCommonHandler.class:?]
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:657) ~[MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_272]

[tomodachi94]

This is standard protocol, but I'm assuming it's the latest version of Forge and ExU2?

[Sainan]

This is forge-1.12.2-14.23.5.2854 which is probably outdated by now. ExU2 didn't get an update since 2019, so still 1.9.9. I don't think the versions matter; ConcurrentModificationException means to me someone forgot a synchronize or similar. :wink:

[tomodachi94]

Oops, linked this to the wrong issue...