TheIllusiveC4
commented
2 years ago Huh, that's weird. Certainly the error is pretty clear about its cause, which is what you've pointed out, so I'll work on a fix for that. However, I must be missing something obvious because I can't tell why the CME is occurring. I'm not iterating through the map at all, the only reference to the map is when calling the merge method. I'm iterating through an unrelated HashSet<String> created from createGroups.
Minecraft Version
1.18.1
What happened?
I just wanted to load a new world.
I already have spotted the issue, cause like the log I attached at the bottom shows, it is a "ConcurrentModificationException" and I found this code snippet: https://github.com/TheIllusiveC4/VeinMining/blob/1.18.x/forge/src/main/java/top/theillusivec4/veinmining/veinmining/logic/BlockGroups.java#L47-L48 There you change the map, while iterating over it, which is not allowed and lead to random crashes, but only sometimes and under some vms never. The two possible fixes are:
How do you trigger this bug?
Load a new world.
Loader
Forge
Loader Version
39.0.75
Mod Version
1.18.1-0.16
Relevant Log Outputs
Error in log
[09Feb2022 13:41:13.472] [Server thread/ERROR] [net.minecraftforge.fml.javafmlmod.FMLModContainer/]: Exception caught during firing event: null Index: 1 Listeners: 0: NORMAL 1: net.minecraftforge.eventbus.EventBus$$Lambda$4519/0x00000008018f2470@96a649f java.util.ConcurrentModificationException at java.base/java.util.HashMap.merge(HashMap.java:1385) at TRANSFORMER/veinmining@1.18.1-0.16/top.theillusivec4.veinmining.veinmining.logic.BlockGroups.init(BlockGroups.java:48) at TRANSFORMER/veinmining@1.18.1-0.16/top.theillusivec4.veinmining.veinmining.logic.BlockProcessor.rebuild(BlockProcessor.java:43) at TRANSFORMER/veinmining@1.18.1-0.16/top.theillusivec4.veinmining.VeinMiningMod.bakeConfigs(VeinMiningMod.java:98) at TRANSFORMER/veinmining@1.18.1-0.16/top.theillusivec4.veinmining.VeinMiningMod.configLoading(VeinMiningMod.java:82) at MC-BOOTSTRAP/eventbus@5.0.3/net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:247) at MC-BOOTSTRAP/eventbus@5.0.3/net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:239) at MC-BOOTSTRAP/eventbus@5.0.3/net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) at MC-BOOTSTRAP/eventbus@5.0.3/net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) at LAYER PLUGIN/javafmllanguage@1.18.1-39.0.75/net.minecraftforge.fml.javafmlmod.FMLModContainer.lambda$new$0(FMLModContainer.java:55) at LAYER PLUGIN/fmlcore@1.18.1-39.0.75/net.minecraftforge.fml.ModContainer.lambda$dispatchConfigEvent$7(ModContainer.java:149) at java.base/java.util.Optional.ifPresent(Optional.java:178) at LAYER PLUGIN/fmlcore@1.18.1-39.0.75/net.minecraftforge.fml.ModContainer.dispatchConfigEvent(ModContainer.java:149) at LAYER PLUGIN/fmlcore@1.18.1-39.0.75/net.minecraftforge.fml.config.ModConfig.fireEvent(ModConfig.java:90) at LAYER PLUGIN/fmlcore@1.18.1-39.0.75/net.minecraftforge.fml.config.ConfigTracker.openConfig(ConfigTracker.java:76) at LAYER PLUGIN/fmlcore@1.18.1-39.0.75/net.minecraftforge.fml.config.ConfigTracker.lambda$loadConfigs$1(ConfigTracker.java:64) at java.base/java.lang.Iterable.forEach(Iterable.java:75) at java.base/java.util.Collections$SynchronizedCollection.forEach(Collections.java:2131) at LAYER PLUGIN/fmlcore@1.18.1-39.0.75/net.minecraftforge.fml.config.ConfigTracker.loadConfigs(ConfigTracker.java:64) at TRANSFORMER/forge@39.0.75/net.minecraftforge.server.ServerLifecycleHooks.handleServerAboutToStart(ServerLifecycleHooks.java:94) at TRANSFORMER/minecraft@1.18.1/net.minecraft.client.server.IntegratedServer.m_7038_(IntegratedServer.java:65) at TRANSFORMER/minecraft@1.18.1/net.minecraft.server.MinecraftServer.m_130011_(MinecraftServer.java:644) at TRANSFORMER/minecraft@1.18.1/net.minecraft.server.MinecraftServer.m_177918_(MinecraftServer.java:258) at java.base/java.lang.Thread.run(Thread.java:833) [13:41:13] [Server thread/ERROR]: Encountered an unexpected exception java.util.ConcurrentModificationException: null at java.util.HashMap.merge(HashMap.java:1385) ~[?:?] at top.theillusivec4.veinmining.veinmining.logic.BlockGroups.init(BlockGroups.java:48) ~[veinmining-forge-1.18.1-0.16.jar%23279!/:task ':jar' property 'archiveVersion'] at top.theillusivec4.veinmining.veinmining.logic.BlockProcessor.rebuild(BlockProcessor.java:43) ~[veinmining-forge-1.18.1-0.16.jar%23279!/:task ':jar' property 'archiveVersion'] at top.theillusivec4.veinmining.VeinMiningMod.bakeConfigs(VeinMiningMod.java:98) ~[veinmining-forge-1.18.1-0.16.jar%23279!/:task ':jar' property 'archiveVersion'] at top.theillusivec4.veinmining.VeinMiningMod.configLoading(VeinMiningMod.java:82) ~[veinmining-forge-1.18.1-0.16.jar%23279!/:task ':jar' property 'archiveVersion'] at net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:247) ~[eventbus-5.0.3.jar%2337!/:?] at net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:239) ~[eventbus-5.0.3.jar%2337!/:?] at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) ~[eventbus-5.0.3.jar%2337!/:?] at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) ~[eventbus-5.0.3.jar%2337!/:?] at net.minecraftforge.fml.javafmlmod.FMLModContainer.lambda$new$0(FMLModContainer.java:55) ~[javafmllanguage-1.18.1-39.0.75.jar%23291!/:?] at net.minecraftforge.fml.ModContainer.lambda$dispatchConfigEvent$7(ModContainer.java:149) ~[fmlcore-1.18.1-39.0.75.jar%23290!/:?] at java.util.Optional.ifPresent(Optional.java:178) ~[?:?] at net.minecraftforge.fml.ModContainer.dispatchConfigEvent(ModContainer.java:149) ~[fmlcore-1.18.1-39.0.75.jar%23290!/:?] at net.minecraftforge.fml.config.ModConfig.fireEvent(ModConfig.java:90) ~[fmlcore-1.18.1-39.0.75.jar%23290!/:?] at net.minecraftforge.fml.config.ConfigTracker.openConfig(ConfigTracker.java:76) ~[fmlcore-1.18.1-39.0.75.jar%23290!/:?] at net.minecraftforge.fml.config.ConfigTracker.lambda$loadConfigs$1(ConfigTracker.java:64) ~[fmlcore-1.18.1-39.0.75.jar%23290!/:?] at java.lang.Iterable.forEach(Iterable.java:75) ~[?:?] at java.util.Collections$SynchronizedCollection.forEach(Collections.java:2131) ~[?:?] at net.minecraftforge.fml.config.ConfigTracker.loadConfigs(ConfigTracker.java:64) ~[fmlcore-1.18.1-39.0.75.jar%23290!/:?] at net.minecraftforge.server.ServerLifecycleHooks.handleServerAboutToStart(ServerLifecycleHooks.java:94) ~[forge-1.18.1-39.0.75-universal.jar%23293!/:?] at net.minecraft.client.server.IntegratedServer.m_7038_(IntegratedServer.java:65) ~[client-1.18.1-20211210.034407-srg.jar%23289!/:?] at net.minecraft.server.MinecraftServer.m_130011_(MinecraftServer.java:644) ~[client-1.18.1-20211210.034407-srg.jar%23289!/:?] at net.minecraft.server.MinecraftServer.m_177918_(MinecraftServer.java:258) ~[client-1.18.1-20211210.034407-srg.jar%23289!/:?] at java.lang.Thread.run(Thread.java:833) [?:?]