I tried to install Forge on Minecraft CraftBukkit Server 1.12.2 in my Ubuntu, but Jar ran incorrectly and the command line showed:
A problem occurred running the Server launcher. java. lang. reflect. Invocation Target Exception
At java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
At java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
At java.base/jdk.internal.reflect.Delegating Method Accessor Impl.invoke (Delegating Method Accessor Impl.java:43)
At java.base/java.lang.reflect.Method.invoke (Method.java:566)
At net.minecraftforge.fml.relauncher.Server Launch Wrapper.run (Server Launch Wrapper.java:70)
At net.minecraftforge.fml.relauncher.Server Launch Wrapper.main (Server Launch Wrapper.java:34)
Caused by: java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders $AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders $AppClassLoader and java.net.URLClassLoader are in module java.base of loader'bootstrap')
At net.minecraft.launchwrapper.Launch. <init> (Launch.java:34)
At net. minecraft. launchwrapper. Launch. main (Launch. java: 28)
... 6 more Can anyone help me?