I don't really know what could be the problem, or the fix. Here is just the console log.

19.06 12:03:02 [Disconnect] User RaineMan11 has disconnected, reason: Server shutting down
19.06 12:03:02 [Multicraft] Server stopped
19.06 12:03:00 [Multicraft] Stopping server!
19.06 12:03:00 [Multicraft] Server shut down
19.06 12:02:59 [Server] [Server thread/INFO Saving chunks for level 'world-Copy-For-snapshot'/The End
19.06 12:02:59 [Server] [Server thread/INFO Saving chunks for level 'world-Copy-For-snapshot'/Nether
19.06 12:02:59 [Server] [Server thread/INFO Saving chunks for level 'world-Copy-For-snapshot'/Overworld
19.06 12:02:59 [Server] [Server thread/INFO Saving worlds
19.06 12:02:59 [Server] [Server thread/INFO Saving players
19.06 12:02:59 [Server] [Server thread/INFO Stopping server
19.06 12:02:59 [Server] INFO at java.lang.Thread.run(Thread.java:745) [?:1.7.0_60]
19.06 12:02:59 [Server] INFO at net.minecraft.server.MinecraftServer.run(SourceFile:422) [custom.jar:?]
19.06 12:02:59 [Server] INFO at net.minecraft.server.MinecraftServer.v(SourceFile:506) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at nt.w(SourceFile:284) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at net.minecraft.server.MinecraftServer.w(SourceFile:596) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at pc.c(SourceFile:135) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at fs.a(SourceFile:167) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at pn.c(SourceFile:52) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at pn.b(SourceFile:86) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at qh.a(SourceFile:133) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at qh.c(SourceFile:278) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at qh.a(SourceFile:226) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at or.a(SourceFile:265) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at or.a(SourceFile:228) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at os.<init>(SourceFile:36) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at ot.c(SourceFile:81) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at ot.e(SourceFile:130) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at azk.a(SourceFile:69) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at azk.a(SourceFile:81) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at azk.a(SourceFile:291) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at uh.a(SourceFile:157) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO at ub.f(SourceFile:1156) ~[custom.jar:?]
19.06 12:02:59 [Server] INFO java.lang.NoClassDefFoundError: Could not initialize class b
19.06 12:02:59 [Server] [Server thread/ERROR Encountered an unexpected exception
19.06 12:02:58 [Server] [Server thread/INFO §bRaineMan11§r joined the game