NoClassDefFoundError

[eternalphane]

Didn't notice anything unusual on my 1.12.2 dedicated server while I found the following lines in the log file:

[05:48:20] [Server thread/ERROR] [FML]: Index: 9 Listeners:
[05:48:20] [Server thread/ERROR] [FML]: 0: HIGHEST
[05:48:20] [Server thread/ERROR] [FML]: 1: ASM: net.quetzi.morpheus.helpers.MorpheusEventHandler@28094f0f bedClicked(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 2: NORMAL
[05:48:20] [Server thread/ERROR] [FML]: 3: ASM: biomesoplenty.common.handler.GrassPathEventHandler@5531feef onBlockRightClick(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 4: ASM: crafttweaker.mc1120.events.CommonEventHandler@4ce3bc97 onPlayerRightClickBlockEvent(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 5: ASM: Block{null} onRightClick(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 6: ASM: mcjty.immcraft.events.ForgeEventHandlers@540563c8 onPlayerRightClickEvent(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 7: ASM: mcmultipart.MCMPCommonProxy@50627105 onPlayerRightClickBlock(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 8: ASM: fi.dy.masa.tellme.event.InteractEventHandler@23b893ce onRightClickBlock(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 9: ASM: net.panoskj.betteroffhand.BetterOffhand@10b39f06 onPlayerInteract(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 10: ASM: mod.chiselsandbits.events.EventPlayerInteract@6a3495c7 interaction(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 11: ASM: com.jaquadro.minecraft.storagedrawers.core.CommonProxy@12242d4d playerRightClick(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/ERROR] [FML]: 12: ASM: crafttweaker.mc1120.events.CommonEventHandler@4ce3bc97 onPlayerInteract(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent;)V
[05:48:20] [Server thread/ERROR] [FML]: 13: ASM: com.sk89q.worldedit.forge.ForgeWorldEdit@405eab9a onPlayerInteract(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent;)V
[05:48:20] [Server thread/ERROR] [FML]: 14: LOWEST
[05:48:20] [Server thread/ERROR] [FML]: 15: ASM: class flaxbeard.immersivepetroleum.common.EventHandler handlePickupItem(Lnet/minecraftforge/event/entity/player/PlayerInteractEvent$RightClickBlock;)V
[05:48:20] [Server thread/FATAL] [net.minecraft.server.MinecraftServer]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: net/minecraft/client/util/ITooltipFlag
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_172]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_172]
	at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:723) [MinecraftServer.class:?]
	at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397) [nz.class:?]
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_172]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/client/util/ITooltipFlag
	at java.lang.Class.getDeclaredMethods0(Native Method) ~[?:1.8.0_172]
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) ~[?:1.8.0_172]
	at java.lang.Class.privateGetMethodRecursive(Class.java:3048) ~[?:1.8.0_172]
	at java.lang.Class.getMethod0(Class.java:3018) ~[?:1.8.0_172]
	at java.lang.Class.getMethod(Class.java:1784) ~[?:1.8.0_172]
	at net.panoskj.betteroffhand.BetterOffhand.onPlayerInteract(BetterOffhand.java:57) ~[BetterOffhand.class:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_351_BetterOffhand_onPlayerInteract_RightClickBlock.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.common.ForgeHooks.onRightClickBlock(ForgeHooks.java:1124) ~[ForgeHooks.class:?]
	at net.minecraft.server.management.PlayerInteractionManager.func_187251_a(PlayerInteractionManager.java:433) ~[or.class:?]
	at net.minecraft.network.NetHandlerPlayServer.func_184337_a(NetHandlerPlayServer.java:741) ~[pa.class:?]
	at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:55) ~[ma.class:?]
	at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:11) ~[ma.class:?]
	at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[hv$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_172]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_172]
	at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
	... 5 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.client.util.ITooltipFlag
	at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:101) ~[launchwrapper-1.12.jar:?]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_172]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_172]
	at java.lang.Class.getDeclaredMethods0(Native Method) ~[?:1.8.0_172]
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) ~[?:1.8.0_172]
	at java.lang.Class.privateGetMethodRecursive(Class.java:3048) ~[?:1.8.0_172]
	at java.lang.Class.getMethod0(Class.java:3018) ~[?:1.8.0_172]
	at java.lang.Class.getMethod(Class.java:1784) ~[?:1.8.0_172]
	at net.panoskj.betteroffhand.BetterOffhand.onPlayerInteract(BetterOffhand.java:57) ~[BetterOffhand.class:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_351_BetterOffhand_onPlayerInteract_RightClickBlock.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.common.ForgeHooks.onRightClickBlock(ForgeHooks.java:1124) ~[ForgeHooks.class:?]
	at net.minecraft.server.management.PlayerInteractionManager.func_187251_a(PlayerInteractionManager.java:433) ~[or.class:?]
	at net.minecraft.network.NetHandlerPlayServer.func_184337_a(NetHandlerPlayServer.java:741) ~[pa.class:?]
	at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:55) ~[ma.class:?]
	at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:11) ~[ma.class:?]
	at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[hv$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_172]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_172]
	at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
	... 5 more