ClassNotFound Exception after installing IC2

  • After installing IC2 1.108.71 and running Minecraft, I simply get a black screen after the Mojang logo, and this appears in my ForgeModLoader-client-0.log:

    EDIT: Using Minecraft 1.4.4, Forge 6.3.0.372, and IC2 version posted above.

    Display Spoiler


    2012-11-18 03:58:47 [FINER] [ForgeModLoader] Sending event FMLConstructionEvent to mod IC2
    2012-11-18 03:58:47 [INFO] [STDERR] java.lang.ClassNotFoundException: ic2.common.ItemIC2
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:141)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at net.minecraftforge.transformers.EventTransformer.buildEvents(EventTransformer.java:54)
    2012-11-18 03:58:47 [INFO] [STDERR] at net.minecraftforge.transformers.EventTransformer.transform(EventTransformer.java:35)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.relauncher.RelaunchClassLoader.runTransformers(RelaunchClassLoader.java:178)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:133)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.Class.forName0(Native Method)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.Class.forName(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:410)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.reflect.Method.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:69)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.post(EventBus.java:268)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:140)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.reflect.Method.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:69)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.post(EventBus.java:268)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:83)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.common.Loader.loadMods(Loader.java:478)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:150)
    2012-11-18 03:58:47 [INFO] [STDERR] at net.minecraft.client.Minecraft.a(Minecraft.java:424)
    2012-11-18 03:58:47 [INFO] [STDERR] at net.minecraft.client.Minecraft.run(Minecraft.java:756)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.Thread.run(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] Caused by: java.lang.VerifyError: Cannot inherit from final class
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.defineClass1(Native Method)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.defineClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.defineClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:134)
    2012-11-18 03:58:47 [INFO] [STDERR] ... 36 more
    2012-11-18 03:58:47 [INFO] [STDERR] Exception in thread "Minecraft main thread" java.lang.NoClassDefFoundError: ic2/common/ItemDebug
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.Class.forName0(Native Method)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.Class.forName(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:410)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.reflect.Method.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:69)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.post(EventBus.java:268)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:140)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.reflect.Method.invoke(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:69)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
    2012-11-18 03:58:47 [INFO] [STDERR] at com.google.common.eventbus.EventBus.post(EventBus.java:268)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:83)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.common.Loader.loadMods(Loader.java:478)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:150)
    2012-11-18 03:58:47 [INFO] [STDERR] at net.minecraft.client.Minecraft.a(Minecraft.java:424)
    2012-11-18 03:58:47 [INFO] [STDERR] at net.minecraft.client.Minecraft.run(Minecraft.java:756)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.Thread.run(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] Caused by: java.lang.ClassNotFoundException: ic2.common.ItemDebug
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:141)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] ... 28 more
    2012-11-18 03:58:47 [INFO] [STDERR] Caused by: java.lang.NoClassDefFoundError: ic2/common/ItemIC2
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.defineClass1(Native Method)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.defineClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.defineClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:134)
    2012-11-18 03:58:47 [INFO] [STDERR] ... 30 more
    2012-11-18 03:58:47 [INFO] [STDERR] Caused by: java.lang.ClassNotFoundException: ic2.common.ItemIC2
    2012-11-18 03:58:47 [INFO] [STDERR] at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:76)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] at java.lang.ClassLoader.loadClass(Unknown Source)
    2012-11-18 03:58:47 [INFO] [STDERR] ... 34 more

    I'm certain Forge was installed correctly, as NEI works just fine. I simply installed the IC2 jar to the mods folder, just like every other modpack. So I don't quite understand why Minecraft cannot find the mod's folders if it's supposed to be looking in the mods folder in the first place.


    Thanks for your time. I hope I don't have to actually put the mod in the minecraft.jar. I've personally never heard of anyone needing to do that with IC2 (or any other mod).

  • I have this odd feeling that you might just have a slightly corrupted IC2 jar. The fact that I'm running the same version of IC2 perfectly fine (and even managed to build a mod against it) tends to reinforce this feeling. Try redownloading it.

  • Did both. Though I did find one problem: I was accidently using a version of Forge made for MC 1.4.5. So I switched it out for 6.3.0.378 which was for 1.4. However, the game still blackscreens. I was really hoping (there's that word again) that it was that simple of a problem, but it's not. I've deleted and reinstalled the mod, deleted and redownloaded the Forge libraries, and just plain deleted everything and started over several times. I've been on this for hours.

    Is there nothing in the error log that points to a solution? Mods don't just decide to not work for one guy of their own volition.

    EDIT: Decided to try a different mod. Dropped Buildcraft into the folder, but I got the same errors (NoClassDefFoundError); just substitute "Buildcraft" for "IC2." So somehow, Forge doesn't know the mods folder exists?I cannot wrap my head around this, but that may be because it's 5 AM.

  • Lol... .such a long discussion but the problem is clear visible. IC2 Beta 1.108 is for Minecraft 1.42. Forge 355 is the last Forge for 1.4.2. Use them both, install Forge correct on a fresh and new Minecraft 1.4.2 Jar and you are good to go.

  • Alright, got it working! Apparently last night I forgot to do one simple thing: when I rolled back the minecraft jar to 1.4.2, I forgot to delete the "version" file and have minecraft download a new one. Now everything works perfectly.

    Thanks for being fairly patient with me. I need to stop doing stuff like this at obscene hours of the morning.