java.lang.NoClassDefFoundError: net/minecraft/client/entity/AbstractClientPlayer
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:424) [MinecraftServer.class:?]
        at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685) [li.class:?]
Caused by: java.lang.ClassNotFoundException: net.minecraft.client.entity.AbstractClientPlayer
        at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191) ~[launchwrapper-1.12.jar:?]
        at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_60]
        at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_60]
        ... 2 more
Caused by: java.lang.NullPointerException
        at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182) ~[launchwrapper-1.12.jar:?]
        at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_60]
        at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_60]
        ... 2 more