[11:58:39 ERROR]: Could not pass event PlayerJoinEvent to RosettaStone vBETA 1.2
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot.jar:git-Spigot-c6871e2-0cd0397]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-c6871e2-0cd0397]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.PlayerList.onPlayerJoin(PlayerList.java:333) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.PlayerList.a(PlayerList.java:159) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.LoginListener.b(LoginListener.java:144) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.LoginListener.c(LoginListener.java:54) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.NetworkManager.a(NetworkManager.java:233) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.ServerConnection.c(ServerConnection.java:140) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.MinecraftServer.D(MinecraftServer.java:825) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.DedicatedServer.D(DedicatedServer.java:399) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.MinecraftServer.C(MinecraftServer.java:665) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at net.minecraft.server.v1_9_R2.MinecraftServer.run(MinecraftServer.java:564) [spigot.jar:git-Spigot-c6871e2-0cd0397]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_161]
Caused by: java.lang.NoSuchMethodError: org.bukkit.entity.Player.getLocale()Ljava/lang/String;
        at us._donut_.rosettastone.PlayerData.onJoin(PlayerData.java:67) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_161]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_161]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_161]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_161]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot.jar:git-Spigot-c6871e2-0cd0397]
        ... 14 more