Minecraft FTB Academy 1.16 install error

OS Name/Version: Unraid 7.0.0

Product Name/Version: AMP Release “Phobos”
v2.6.1.6, built 21/04/2025 13:43

Problem Description:

I’ve been struggling to get the ftb academy 1.16 to run.

First I just selected Feed the Beast (new source) server type and downloaded the mod. When I tried to run it, it would say a server jar wasn’t selected. If i switched from autoselect to the forge-1.16.5-36.2.34.jar that came with the mod I would just get an error.

Then, I found other topics here where I saw that there were instructions to, after the mod files are downloaded, switch the server type to forge and pick the corresponding forge version* of the mod. This did not resolve the issue, I still end up with the same error when trying to start with server JAR on either auto select or the forge one.

*[I selected “36.2.34 (mc 1.16.5)” based on the .jar file that came with the mod download]

Below is is what the console printed out when I tried to start it up:

Console
16:01:07

2025-05-15 16:01:07,060 main WARN Advanced terminal features are not available in this environment
Exception in thread "main" java.lang.IllegalAccessError: class cpw.mods.modlauncher.SecureJarHandler (in unnamed module @0x6107227e) cannot access class sun.security.util.ManifestEntryVerifier (in module java.base) because module java.base does not export sun.security.util to unnamed module @0x6107227e
    at cpw.mods.modlauncher.SecureJarHandler.lambda$static$1(SecureJarHandler.java:45)

main/INFO
16:01:07

ModLauncher running: args [--gameDir, ., --launchTarget, fmlserver, --fml.forgeVersion, 36.2.34, --fml.mcpVersion, 20210115.111550, --fml.mcVersion, 1.16.5, --fml.forgeGroup, net.minecraftforge, nogui]

Console
16:01:07

    at cpw.mods.modlauncher.api.LamdbaExceptionUtils.uncheck(LamdbaExceptionUtils.java:95)

main/INFO
16:01:07

ModLauncher 8.1.3+8.1.3+main-8.1.x.c94d18ec starting: java version 21.0.5 by Eclipse Adoptium

Console
16:01:07

    at cpw.mods.modlauncher.SecureJarHandler.<clinit>(SecureJarHandler.java:45)
    at cpw.mods.modlauncher.Launcher.lambda$new$6(Launcher.java:55)
    at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708)
    at cpw.mods.modlauncher.api.TypesafeMap.computeIfAbsent(TypesafeMap.java:52)
    at cpw.mods.modlauncher.api.TypesafeMap.computeIfAbsent(TypesafeMap.java:47)
    at cpw.mods.modlauncher.Environment.computePropertyIfAbsent(Environment.java:62)
    at cpw.mods.modlauncher.Launcher.<init>(Launcher.java:55)
    at cpw.mods.modlauncher.Launcher.main(Launcher.java:66)
    at net.minecraftforge.server.ServerMain$Runner.runLauncher(ServerMain.java:63)
    at net.minecraftforge.server.ServerMain$Runner.access$100(ServerMain.java:60)
    at net.minecraftforge.server.ServerMain.main(ServerMain.java:57)

I have been able to get a vanilla server running no problem.

Looks like you don’t have the right Java runtime selected, Forge 1.16.5 needs 8 or 11.
There’s a full rundown here:
https://discourse.cubecoders.com/t/setting-up-a-modded-java-minecraft-server/26535#p-50642-h-2-feed-the-beast-21