Please read the rules and FAQ before starting a new topic

Failed to start the minecraft server java.lang.IllegalArgumentException: Unsupported class file major version 63

Posted October 10, 20222 yr

Hi everyone !, I have a minecraft 1.18.2 server with 15 mods. A couple of days ago I updated to Windows 11, and I have had this recurring error, I have tried to reinstall the forge server with all versions of java JDK (17, 18 and 19)(also i try to start the old server with the same java versions but nothing happens). But with none of the three I have been able to overcome this error, I appreciate any help or idea to solve it!, thanks!

(The server runs smoothly when I don't include the mods)


D:\User\Desktop\Server>REM Forge requires a configured set of both JVM and program arguments.

D:\User\Desktop\Server>REM Add custom JVM arguments to the user_jvm_args.txt

D:\User\Desktop\Server>REM Add custom program arguments {such as nogui} to this file in the next line before the  or

D:\User\Desktop\Server>REM  pass them to this script directly

D:\User\Desktop\Server>java @user_jvm_args.txt @libraries/net/minecraftforge/forge/1.18.2-40.1.76/win_args.txt
2022-10-10 17:20:20,957 main WARN Advanced terminal features are not available in this environment
[17:20:21] [main/INFO] [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher running: args [--launchTarget, forgeserver, --fml.forgeVersion, 40.1.76, --fml.mcVersion, 1.18.2, --fml.forgeGroup, net.minecraftforge, --fml.mcpVersion, 20220404.173914, -nogui]
[17:20:21] [main/INFO] [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher 9.1.3+9.1.3+main.9b69c82a starting: java version 19 by Oracle Corporation
[17:20:21] [main/INFO] [op.OptiFineTransformationService/]: OptiFineTransformationService.onLoad
[17:20:21] [main/INFO] [op.OptiFineTransformationService/]: OptiFine ZIP file URL: union:/D:/User/Desktop/Server/mods/OptiFine-1.18.2_HD_U_H9_pre1.jar%2339!/
[17:20:21] [main/INFO] [op.OptiFineTransformationService/]: OptiFine ZIP file: D:\User\Desktop\Server\mods\OptiFine-1.18.2_HD_U_H9_pre1.jar
[17:20:21] [main/INFO] [op.OptiFineTransformer/]: Target.PRE_CLASS is available
[17:20:21] [main/INFO] [mixin/]: SpongePowered MIXIN Subsystem Version=0.8.5 Source=union:/D:/User/Desktop/Server/libraries/org/spongepowered/mixin/0.8.5/mixin-0.8.5.jar%2314!/ Service=ModLauncher Env=SERVER
[17:20:21] [main/INFO] [op.OptiFineTransformationService/]: OptiFineTransformationService.initialize
[17:20:22] [main/WARN] [ne.mi.fm.lo.mo.ModFileParser/LOADING]: Mod file D:\User\Desktop\Server\libraries\net\minecraftforge\fmlcore\1.18.2-40.1.76\fmlcore-1.18.2-40.1.76.jar is missing mods.toml file
[17:20:22] [main/WARN] [ne.mi.fm.lo.mo.ModFileParser/LOADING]: Mod file D:\User\Desktop\Server\libraries\net\minecraftforge\javafmllanguage\1.18.2-40.1.76\javafmllanguage-1.18.2-40.1.76.jar is missing mods.toml file
[17:20:22] [main/WARN] [ne.mi.fm.lo.mo.ModFileParser/LOADING]: Mod file D:\User\Desktop\Server\libraries\net\minecraftforge\lowcodelanguage\1.18.2-40.1.76\lowcodelanguage-1.18.2-40.1.76.jar is missing mods.toml file
[17:20:22] [main/WARN] [ne.mi.fm.lo.mo.ModFileParser/LOADING]: Mod file D:\User\Desktop\Server\libraries\net\minecraftforge\mclanguage\1.18.2-40.1.76\mclanguage-1.18.2-40.1.76.jar is missing mods.toml file
[17:20:23] [main/INFO] [ne.mi.fm.lo.mo.JarInJarDependencyLocator/]: Found 1 dependencies adding them to mods collection
[17:20:23] [main/INFO] [op.OptiFineTransformationService/]: OptiFineTransformationService.transformers
[17:20:23] [main/INFO] [op.OptiFineTransformer/]: Targets: 359
[17:20:24] [main/INFO] [op.OptiFineTransformationService/]: additionalClassesLocator: [optifine., net.optifine.]
[17:20:26] [main/INFO] [mixin/]: Compatibility level set to JAVA_17
[17:20:26] [main/INFO] [cp.mo.mo.LaunchServiceHandler/MODLAUNCHER]: Launching target 'forgeserver' with arguments [-nogui]
[17:20:26] [main/ERROR] [minecraft/Main]: Failed to start the minecraft server
java.lang.IllegalArgumentException: Unsupported class file major version 63
        at org.objectweb.asm.ClassReader.<init>(ClassReader.java:199) ~[asm-9.2.jar:?] {}
        at org.objectweb.asm.ClassReader.<init>(ClassReader.java:180) ~[asm-9.2.jar:?] {}
        at org.objectweb.asm.ClassReader.<init>(ClassReader.java:166) ~[asm-9.2.jar:?] {}
        at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:75) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.TransformingClassLoader.maybeTransformClassBytes(TransformingClassLoader.java:50) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.cl.ModuleClassLoader.getMaybeTransformedClassBytes(ModuleClassLoader.java:245) ~[securejarhandler-1.0.3.jar:?] {}
        at cpw.mods.modlauncher.TransformingClassLoader.buildTransformedClassNodeFor(TransformingClassLoader.java:58) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.TransformerClassWriter.computeHierarchyFromFile(TransformerClassWriter.java:149) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.TransformerClassWriter.computeHierarchy(TransformerClassWriter.java:112) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.TransformerClassWriter.getSupers(TransformerClassWriter.java:83) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.TransformerClassWriter.getCommonSuperClass(TransformerClassWriter.java:66) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at org.objectweb.asm.SymbolTable.addMergedType(SymbolTable.java:1202) ~[asm-9.2.jar:?] {}
        at org.objectweb.asm.Frame.merge(Frame.java:1299) ~[asm-9.2.jar:?] {}
        at org.objectweb.asm.Frame.merge(Frame.java:1197) ~[asm-9.2.jar:?] {}
        at org.objectweb.asm.MethodWriter.computeAllFrames(MethodWriter.java:1610) ~[asm-9.2.jar:?] {}
        at org.objectweb.asm.MethodWriter.visitMaxs(MethodWriter.java:1546) ~[asm-9.2.jar:?] {}
        at org.objectweb.asm.tree.MethodNode.accept(MethodNode.java:769) ~[asm-tree-9.2.jar:?] {}
        at org.objectweb.asm.tree.MethodNode.accept(MethodNode.java:649) ~[asm-tree-9.2.jar:?] {}
        at org.objectweb.asm.tree.ClassNode.accept(ClassNode.java:452) ~[asm-tree-9.2.jar:?] {}
        at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:133) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.TransformingClassLoader.maybeTransformClassBytes(TransformingClassLoader.java:50) ~[modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.cl.ModuleClassLoader.readerToClass(ModuleClassLoader.java:110) ~[securejarhandler-1.0.3.jar:?] {}
        at cpw.mods.cl.ModuleClassLoader.lambda$findClass$16(ModuleClassLoader.java:216) ~[securejarhandler-1.0.3.jar:?] {}
        at cpw.mods.cl.ModuleClassLoader.loadFromModule(ModuleClassLoader.java:226) ~[securejarhandler-1.0.3.jar:?] {}
        at cpw.mods.cl.ModuleClassLoader.findClass(ModuleClassLoader.java:216) ~[securejarhandler-1.0.3.jar:?] {}
        at cpw.mods.cl.ModuleClassLoader.loadClass(ModuleClassLoader.java:132) ~[securejarhandler-1.0.3.jar:?] {}
        at java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[?:?] {}
        at net.minecraft.server.Main.main(Main.java:104) ~[server-1.18.2-20220404.173914-srg.jar%2353!/:?] {re:classloading}
        at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[?:?] {}
        at java.lang.reflect.Method.invoke(Method.java:578) ~[?:?] {}
        at net.minecraftforge.fml.loading.targets.CommonServerLaunchHandler.lambda$launchService$0(CommonServerLaunchHandler.java:32) ~[fmlloader-1.18.2-40.1.76.jar%2317!/:?] {}
        at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:53) [modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:71) [modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.Launcher.run(Launcher.java:106) [modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.Launcher.main(Launcher.java:77) [modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) [modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) [modlauncher-9.1.3.jar%235!/:?] {}
        at cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:149) [bootstraplauncher-1.0.0.jar:?] {}

Quote

October 10, 20222 yr

Use java 17

Boilerplate:

If you don't post your logs/debug.log we can't help you. For curseforge you need to enable the forge debug.log in its minecraft settings. You should also post your crash report if you have one.

If there is no error in the log file and you don't have a crash report then post the launcher_log.txt from the minecraft folder. Again for curseforge this will be in your curseforge/minecraft/Install

Large files should be posted to a file sharing site like https://gist.github.com You should also read the support forum sticky post.

Quote

October 10, 20222 yr

Author

3 minutes ago, warjort said:

Use java 17

I already tried it, it doesn't work

Quote

October 10, 20222 yr

"It doesn't work" is not an answerable question.

Boilerplate:

If you don't post your logs/debug.log we can't help you. For curseforge you need to enable the forge debug.log in its minecraft settings. You should also post your crash report if you have one.

If there is no error in the log file and you don't have a crash report then post the launcher_log.txt from the minecraft folder. Again for curseforge this will be in your curseforge/minecraft/Install

Large files should be posted to a file sharing site like https://gist.github.com You should also read the support forum sticky post.

Quote

October 10, 20222 yr

I do so see you trying to use optifine on the server which is pointless. All it will do is potentially break things there. 🙂

Edited October 10, 20222 yr by warjort

Boilerplate:

If you don't post your logs/debug.log we can't help you. For curseforge you need to enable the forge debug.log in its minecraft settings. You should also post your crash report if you have one.

If there is no error in the log file and you don't have a crash report then post the launcher_log.txt from the minecraft folder. Again for curseforge this will be in your curseforge/minecraft/Install

Large files should be posted to a file sharing site like https://gist.github.com You should also read the support forum sticky post.

Quote

October 10, 20222 yr

Author

8 minutes ago, warjort said:

I do so see you trying to use optifine on the server which is pointless. All it will do is potentially break things there. 🙂

I managed to solve the java problem by deleting all the versions and using a "jarfix" file to solve the interferences. But definitely the optifine was the problem. Thank you so much !, I had 3 days with this, u save me.

Quote

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.

Reply to this topic...

https://forums.minecraftforge.net/topic/117404-failed-to-start-the-minecraft-server-javalangillegalargumentexception-unsupported-class-file-major-version-63/

Followers

Go to topic listing

IPS spam blocked by CleanTalk.

Announcements

Mod for world Templates

WorldTools (Constructor) Allows you to capture and save detailed snapshots of server worlds (terrain, entities, metadata, etc.).

By moyiv · 6 hours ago6 hr
jarJar not working

Try replacing implementation with minecraftLibrary. Dependencies in the minecraftLibrary configuration are added to your compile and runtime classpaths in ForgeGradle 6.

By Jonathing · 14 hours ago14 hr
Failed loading villager cartographer registered at cartographer - frozen tick

Allocated 10 Gb of ram. Could try again with more but I read using too much can slow things down as well. Going to try another big modpack and see if i can replicate the problem. It seems like this cartographer problem is kind of popular and doesn't have a solid solution yet, but i suspect its some generation mod since it's a crash that happens when specific chunks are being loaded. so i'll still try to lookout for what mod it could be as i add. i'll report back after testing as you suggested for a bit

By chemba21 · 19 hours ago19 hr
Failed loading villager cartographer registered at cartographer - frozen tick

I have no idea - is enough RAM allocated?
Do other pre-configured modpacks work? Maybe use such a modpack as working base and add new mods one by one

By TileEntity · 19 hours ago19 hr
Minecraft Mod Gradle Build not working

<repository> looks like a placeholder
url "https://maven.minecraftforge.net/<repository>"

By TileEntity · 19 hours ago19 hr

Sign In

Failed to start the minecraft server java.lang.IllegalArgumentException: Unsupported class file major version 63

Featured Replies

Join the conversation

Posts

Mod for world Templates

jarJar not working

Failed loading villager cartographer registered at cartographer - frozen tick

Failed loading villager cartographer registered at cartographer - frozen tick

Minecraft Mod Gradle Build not working

Who's Online (See full list)

Important Information

Account

Navigation

Search

Configure browser push notifications

Chrome (Android)

Chrome (Desktop)

Safari (iOS 16.4+)

Safari (macOS)

Edge (Android)

Edge (Desktop)

Firefox (Android)

Firefox (Desktop)