java -jar forge.jar --nogui
A problem occurred running the Server launcher.java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:62)
        at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:31)
Caused by: java.lang.NoClassDefFoundError: org/apache/logging/log4j/Level
        at net.minecraft.launchwrapper.Launch.launch(Launch.java:94)
        at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
        ... 6 more
Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.Level
        at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        ... 8 more