Minecraft modded server "Exception in thread "main" java.lang.IllegalAccessError"

[mayu_bros]

I can’t figure out what the issue is with this error message I’m given when trying to run the server:

2023-06-10 22:52:45,616 main WARN Advanced terminal features are not available in this environment
[22:52:45] [main/INFO] [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher running: args [–gameDir, ., --launchTarget, fmlserver, --fml.forgeVersion, 36.2.39, --fml.mcpVersion, 20210115.111550, --fml.mcVersion, 1.16.5, --fml.forgeGroup, net.minecraftforge, nogui]
[22:52:45] [main/INFO] [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher 8.1.3+8.1.3+main-8.1.x.c94d18ec starting: java version 20 by Oracle Corporation
Exception in thread “main” java.lang.IllegalAccessError: class cpw.mods.modlauncher.SecureJarHandler (in unnamed module @0x75f32542) cannot access class sun.security.util.ManifestEntryVerifier (in module java.base) because module java.base does not export sun.security.util to unnamed module @0x75f32542
at cpw.mods.modlauncher.SecureJarHandler.lambda$static$1(SecureJarHandler.java:45)
at cpw.mods.modlauncher.api.LamdbaExceptionUtils.uncheck(LamdbaExceptionUtils.java:95)
at cpw.mods.modlauncher.SecureJarHandler.(SecureJarHandler.java:45)
at cpw.mods.modlauncher.Launcher.lambda$new$6(Launcher.java:55)
at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708)
at cpw.mods.modlauncher.api.TypesafeMap.computeIfAbsent(TypesafeMap.java:52)
at cpw.mods.modlauncher.api.TypesafeMap.computeIfAbsent(TypesafeMap.java:47)
at cpw.mods.modlauncher.Environment.computePropertyIfAbsent(Environment.java:62)
at cpw.mods.modlauncher.Launcher.(Launcher.java:55)
at cpw.mods.modlauncher.Launcher.main(Launcher.java:66)
at net.minecraftforge.server.ServerMain$Runner.runLauncher(ServerMain.java:49)
at net.minecraftforge.server.ServerMain$Runner.access$100(ServerMain.java:46)
at net.minecraftforge.server.ServerMain.main(ServerMain.java:43)

I have both java 8 and Java 20 development kit installed on my pc. any ideas?

[ThePotatoKing]

Forge 1.16 needs Java 8. (Configuration → Java and Memory → Java Version)

Forge Frequently Asked Questions

Forge Frequently Asked Questions How do I run Forge using: start.sh/start.bat? No need! AMP handles all that for you. Just select the version of Forge you’ll need, hit update, and start your server. Where do I put custom start up arguments? You can find this options under: Configuration → Java and Memory → Additional java options I installed a modpack using AMP’s FTB downloader, why did it start in Vanilla? or The update manager reported a successful update, but ./Minecraft/minecraft_server.j…

[mayu_bros]

When I try to run it with just Java 8 installed, I now get this error message:

Error: opening registry key ‘Software\JavaSoft\Java Runtime Environment’
Error: could not find java.dll
Error: Could not find Java SE Runtime Environment.

[ThePotatoKing]

Something might be wrong with the Java 8 instillation if that’s all you’re getting in the console.

[mayu_bros]

I’ve tried reinstalling it before and nothing changes with that message, it remains the same. i’m running java 8 update 371 (64-bit).