why does it crash how to fix?

20.02 09:10:25 [Multicraft] Server stopped 20.02 09:10:25 [Multicraft] Looks like a crash, check the server console. Return value: 1 20.02 09:10:25 [Multicraft] Restarting crashed server in 5 seconds 20.02 09:10:25 [Multicraft] Server shut down (starting) 20.02 09:10:25 [Server] INFO at cpw.mods.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:12) 20.02 09:10:25 [Server] INFO at cpw.mods.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:25) 20.02 09:10:25 [Server] INFO at java.lang.Class.forName(Class.java:348) 20.02 09:10:25 [Server] INFO at java.lang.Class.forName0(Native Method) 20.02 09:10:25 [Server] INFO at java.lang.ClassLoader.loadClass(ClassLoader.java:357) 20.02 09:10:25 [Server] INFO at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) 20.02 09:10:25 [Server] INFO at java.lang.ClassLoader.loadClass(ClassLoader.java:424) 20.02 09:10:25 [Server] INFO at java.net.URLClassLoader.findClass(URLClassLoader.java:381) 20.02 09:10:25 [Server] INFO You will need to add them to your server before FML and Forge will run successfully.java.lang.ClassNotFoundException: net.minecraft.launchwrapper.Launch 20.02 09:10:25 [Server] INFO We appear to be missing one or more essential library files. 20.02 09:10:25 [Server] INFO Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0