NoClassDefError nightmare

[Turtledove]

I've completed and generated a build of a mod I thought was ready to export. It runs without issue on runClient, but when I run MC with the mod's jar file, it spits out a NoClassDefError for my entity classes during entity and renderer registration. I've checked the jar file with 7zip and the class files are all there, so I'm suspecting I've unintentionally reached across logical sides here and there, meaning I've got a long refactor in front of me...sigh...

 

During general development, is there a fool-proof way of checking this? I don't see any warnings in the compiler's console when I do, so tracking down these things after the fact is a horrible nightmare...

Edited July 10, 2021 by Turtledove

[Turtledove]

14 minutes ago, diesieben07 said:

No. Show your code and the error.

The error in question:

Time: 7/10/21 1:09 PM
Description: Mod loading error has occurred

java.lang.Exception: Mod Loading has failed
	at net.minecraftforge.fml.CrashReportExtender.dumpModLoadingCrashReport(CrashReportExtender.java:85) ~[?:?] {re:classloading}
	at net.minecraftforge.fml.client.ClientModLoader.completeModLoading(ClientModLoader.java:188) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.lambda$null$1(Minecraft.java:494) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.util.Util.func_215077_a(SourceFile:404) ~[?:?] {re:classloading}
	at net.minecraft.client.Minecraft.lambda$new$2(Minecraft.java:490) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.ResourceLoadProgressGui.func_230430_a_(ResourceLoadProgressGui.java:113) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.renderer.GameRenderer.func_195458_a(GameRenderer.java:480) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.func_195542_b(Minecraft.java:953) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:584) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.main.Main.main(Main.java:184) ~[minecraft-1.16.3-client.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_241] {}
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_241] {}
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_241] {}
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_241] {}
	at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:51) ~[forge-1.16.3-34.1.0-launcher.jar:34.1] {}
	at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.Launcher.run(Launcher.java:81) [modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.Launcher.main(Launcher.java:65) [modlauncher-7.0.1.jar:?] {}
	at io.github.zekerzhayard.forgewrapper.installer.Main.main(Main.java:50) [ForgeWrapper-1.4.2.jar:?] {}
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_241] {}
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_241] {}
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_241] {}
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_241] {}
	at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196) [NewLaunch.jar:?] {}
	at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231) [NewLaunch.jar:?] {}
	at org.multimc.EntryPoint.listen(EntryPoint.java:143) [NewLaunch.jar:?] {}
	at org.multimc.EntryPoint.main(EntryPoint.java:34) [NewLaunch.jar:?] {}


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Render thread
Stacktrace:
	at java.lang.ClassLoader.findClass(Unknown Source) ~[?:1.8.0_241] {}
-- MOD withernauts --
Details:
	Caused by 0: java.lang.BootstrapMethodError: java.lang.NoClassDefFoundError: com/github/alexthe666/citadel/animation/IAnimatedEntity
		at com.withernauts.withernauts.entity.EntityRegistry.<clinit>(EntityRegistry.java:23) ~[?:1.0] {re:classloading}
		at java.lang.Class.forName0(Native Method) ~[?:1.8.0_241] {}
		at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_241] {}
		at net.minecraftforge.fml.AutomaticEventSubscriber.lambda$inject$6(AutomaticEventSubscriber.java:75) ~[?:?] {re:classloading}
		at java.util.ArrayList.forEach(Unknown Source) ~[?:1.8.0_241] {}
		at net.minecraftforge.fml.AutomaticEventSubscriber.inject(AutomaticEventSubscriber.java:62) ~[?:?] {re:classloading}
		at net.minecraftforge.fml.javafmlmod.FMLModContainer.constructMod(FMLModContainer.java:91) ~[?:34.1] {re:classloading}
		at net.minecraftforge.fml.ModContainer.lambda$buildTransitionHandler$5(ModContainer.java:111) ~[?:?] {re:classloading}
		at java.util.concurrent.CompletableFuture$AsyncRun.run(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.CompletableFuture$AsyncRun.exec(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.ForkJoinTask.doExec(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) ~[?:1.8.0_241] {}

	Caused by 1: java.lang.NoClassDefFoundError: com/github/alexthe666/citadel/animation/IAnimatedEntity
		at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.8.0_241] {}
		at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.8.0_241] {}
		at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.8.0_241] {}
		at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:136) ~[modlauncher-7.0.1.jar:?] {re:classloading}
		at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:97) ~[modlauncher-7.0.1.jar:?] {re:classloading}
		at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241] {}
		at net.minecraftforge.eventbus.EventSubclassTransformer.buildEvents(EventSubclassTransformer.java:62) ~[eventbus-3.0.3-service.jar:?] {}
		at net.minecraftforge.eventbus.EventSubclassTransformer.transform(EventSubclassTransformer.java:44) ~[eventbus-3.0.3-service.jar:?] {}
		at net.minecraftforge.eventbus.EventBusEngine.processClass(EventBusEngine.java:21) ~[eventbus-3.0.3-service.jar:?] {}
		at net.minecraftforge.eventbus.service.ModLauncherService.processClassWithFlags(ModLauncherService.java:20) ~[eventbus-3.0.3-service.jar:3.0.3+63+master.b6b4769] {}
		at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:85) ~[modlauncher-7.0.1.jar:?] {}
		at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:119) ~[modlauncher-7.0.1.jar:?] {}
		at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:256) ~[modlauncher-7.0.1.jar:?] {}
		at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:135) ~[modlauncher-7.0.1.jar:?] {re:classloading}
		at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:97) ~[modlauncher-7.0.1.jar:?] {re:classloading}
		at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241] {}
		at net.minecraftforge.eventbus.EventSubclassTransformer.buildEvents(EventSubclassTransformer.java:62) ~[eventbus-3.0.3-service.jar:?] {}
		at net.minecraftforge.eventbus.EventSubclassTransformer.transform(EventSubclassTransformer.java:44) ~[eventbus-3.0.3-service.jar:?] {}
		at net.minecraftforge.eventbus.EventBusEngine.processClass(EventBusEngine.java:21) ~[eventbus-3.0.3-service.jar:?] {}
		at net.minecraftforge.eventbus.service.ModLauncherService.processClassWithFlags(ModLauncherService.java:20) ~[eventbus-3.0.3-service.jar:3.0.3+63+master.b6b4769] {}
		at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:85) ~[modlauncher-7.0.1.jar:?] {}
		at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:119) ~[modlauncher-7.0.1.jar:?] {}
		at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:256) ~[modlauncher-7.0.1.jar:?] {}
		at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:135) ~[modlauncher-7.0.1.jar:?] {re:classloading}
		at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:97) ~[modlauncher-7.0.1.jar:?] {re:classloading}
		at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241] {}
		at com.withernauts.withernauts.entity.EntityRegistry.<clinit>(EntityRegistry.java:23) ~[?:1.0] {re:classloading}
		at java.lang.Class.forName0(Native Method) ~[?:1.8.0_241] {}
		at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_241] {}
		at net.minecraftforge.fml.AutomaticEventSubscriber.lambda$inject$6(AutomaticEventSubscriber.java:75) ~[?:?] {re:classloading}
		at java.util.ArrayList.forEach(Unknown Source) ~[?:1.8.0_241] {}
		at net.minecraftforge.fml.AutomaticEventSubscriber.inject(AutomaticEventSubscriber.java:62) ~[?:?] {re:classloading}
		at net.minecraftforge.fml.javafmlmod.FMLModContainer.constructMod(FMLModContainer.java:91) ~[?:34.1] {re:classloading}
		at net.minecraftforge.fml.ModContainer.lambda$buildTransitionHandler$5(ModContainer.java:111) ~[?:?] {re:classloading}
		at java.util.concurrent.CompletableFuture$AsyncRun.run(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.CompletableFuture$AsyncRun.exec(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.ForkJoinTask.doExec(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) ~[?:1.8.0_241] {}
		at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) ~[?:1.8.0_241] {}

	Mod File: modid-1.0.jar
	Failure message: Withernauts (withernauts) has failed to load correctly
		java.lang.BootstrapMethodError: java.lang.NoClassDefFoundError: com/github/alexthe666/citadel/animation/IAnimatedEntity
	Mod Version: 1.0
	Mod Issue URL: NOT PROVIDED
	Exception message: java.lang.ClassNotFoundException: com.github.alexthe666.citadel.animation.IAnimatedEntity
Stacktrace:
	at java.lang.ClassLoader.findClass(Unknown Source) ~[?:1.8.0_241] {}
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241] {}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:105) ~[modlauncher-7.0.1.jar:?] {re:classloading}
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241] {}
	at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.8.0_241] {}
	at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.8.0_241] {}
	at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.8.0_241] {}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:136) ~[modlauncher-7.0.1.jar:?] {re:classloading}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:97) ~[modlauncher-7.0.1.jar:?] {re:classloading}
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241] {}
	at net.minecraftforge.eventbus.EventSubclassTransformer.buildEvents(EventSubclassTransformer.java:62) ~[eventbus-3.0.3-service.jar:?] {}
	at net.minecraftforge.eventbus.EventSubclassTransformer.transform(EventSubclassTransformer.java:44) ~[eventbus-3.0.3-service.jar:?] {}
	at net.minecraftforge.eventbus.EventBusEngine.processClass(EventBusEngine.java:21) ~[eventbus-3.0.3-service.jar:?] {}
	at net.minecraftforge.eventbus.service.ModLauncherService.processClassWithFlags(ModLauncherService.java:20) ~[eventbus-3.0.3-service.jar:3.0.3+63+master.b6b4769] {}
	at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:85) ~[modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:119) ~[modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:256) ~[modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:135) ~[modlauncher-7.0.1.jar:?] {re:classloading}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:97) ~[modlauncher-7.0.1.jar:?] {re:classloading}
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241] {}
	at net.minecraftforge.eventbus.EventSubclassTransformer.buildEvents(EventSubclassTransformer.java:62) ~[eventbus-3.0.3-service.jar:?] {}
	at net.minecraftforge.eventbus.EventSubclassTransformer.transform(EventSubclassTransformer.java:44) ~[eventbus-3.0.3-service.jar:?] {}
	at net.minecraftforge.eventbus.EventBusEngine.processClass(EventBusEngine.java:21) ~[eventbus-3.0.3-service.jar:?] {}
	at net.minecraftforge.eventbus.service.ModLauncherService.processClassWithFlags(ModLauncherService.java:20) ~[eventbus-3.0.3-service.jar:3.0.3+63+master.b6b4769] {}
	at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:85) ~[modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:119) ~[modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:256) ~[modlauncher-7.0.1.jar:?] {}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:135) ~[modlauncher-7.0.1.jar:?] {re:classloading}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:97) ~[modlauncher-7.0.1.jar:?] {re:classloading}
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241] {}
	at com.withernauts.withernauts.entity.EntityRegistry.<clinit>(EntityRegistry.java:23) ~[?:1.0] {re:classloading}
	at java.lang.Class.forName0(Native Method) ~[?:1.8.0_241] {}
	at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_241] {}
	at net.minecraftforge.fml.AutomaticEventSubscriber.lambda$inject$6(AutomaticEventSubscriber.java:75) ~[?:?] {re:classloading}
	at java.util.ArrayList.forEach(Unknown Source) ~[?:1.8.0_241] {}
	at net.minecraftforge.fml.AutomaticEventSubscriber.inject(AutomaticEventSubscriber.java:62) ~[?:?] {re:classloading}
	at net.minecraftforge.fml.javafmlmod.FMLModContainer.constructMod(FMLModContainer.java:91) ~[?:34.1] {re:classloading}
	at net.minecraftforge.fml.ModContainer.lambda$buildTransitionHandler$5(ModContainer.java:111) ~[?:?] {re:classloading}
	at java.util.concurrent.CompletableFuture$AsyncRun.run(Unknown Source) ~[?:1.8.0_241] {}
	at java.util.concurrent.CompletableFuture$AsyncRun.exec(Unknown Source) ~[?:1.8.0_241] {}
	at java.util.concurrent.ForkJoinTask.doExec(Unknown Source) ~[?:1.8.0_241] {}
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source) ~[?:1.8.0_241] {}
	at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) ~[?:1.8.0_241] {}
	at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) ~[?:1.8.0_241] {}

And the relevant class:

https://github.com/CyclingDank/withernauts/blob/main/src/main/java/com/withernauts/withernauts/entity/EntityRegistry.java

Edited July 10, 2021 by Turtledove

[Turtledove]

7 minutes ago, diesieben07 said:

Your registration code is broken. You must use DeferredRegister or registry events. Do not create registry entries (like EntityType) in static initializers. Refer to the documentation on registries for more info.

The error in the log is because your code has hard references to the Citadel library, but you did not install it or declare this dependency in your mods.toml. If you had done the latter, Forge would have displayed a useful error screen, mentioning the missing dependency.

The latter was it. I thought "If I have the library linked in my dev environment, surely when I generate the jar it'd be linked to!" But nope, just being dumb.

As for the registration code, it currently works without issue, but is there a reason why I shouldn't combine static initializers with the registry event? Reflection was the obvious choice as well to reduce the amount of code I had to type for all my dozens and dozens of entities.

 

Thanks for your input as always 👍