[16:52:50 ERROR]: Could not pass event PlayerJoinEvent to Core v1.0
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:305) ~[spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62) ~[spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:502) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:487) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.PlayerList.onPlayerJoin(PlayerList.java:
262) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.PlayerList.a(PlayerList.java:147) [spigo
t-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.LoginListener.b(LoginListener.java:109)
[spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.LoginListener.c(LoginListener.java:41) [
spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.NetworkManager.a(NetworkManager.java:159
) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.ServerConnection.c(ServerConnection.java
:82) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:7
85) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:3
16) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:6
23) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java
:526) [spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        at java.lang.Thread.run(Unknown Source) [?:1.7.0_71]
Caused by: java.lang.NoClassDefFoundError: com/heroversemc/utils/UUIDFetcher
        at com.heroversemc.core.user.User.<init>(User.java:32) ~[?:?]
        at com.heroversemc.core.user.User.getUser(User.java:114) ~[?:?]
        at com.heroversemc.core.user.User.getUser(User.java:118) ~[?:?]
        at com.heroversemc.listeners.PlayerJoinQuit.onPlayerJoin(PlayerJoinQuit.
java:14) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0
_71]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0
_71]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1
.7.0_71]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.7.0_71]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:301) ~[spigot-1.8-R0.1-SNAPSHOT.jar:git-Spigot-8dc4297-adc129a]
        ... 14 more