Bukkit

[16:43:14 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'frie
nds' in plugin MyFriends vv2.0
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spi
got1543.jar:git-Spigot-1543]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:18
1) ~[spigot1543.jar:git-Spigot-1543]
        at org.bukkit.craftbukkit.v1_7_R3.CraftServer.dispatchCommand(CraftServe
r.java:767) ~[spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.PlayerConnection.handleCommand(PlayerCon
nection.java:1015) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.PlayerConnection.a(PlayerConnection.java
:845) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.PacketPlayInChat.a(PacketPlayInChat.java
:28) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.PacketPlayInChat.handle(PacketPlayInChat
.java:65) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.NetworkManager.a(NetworkManager.java:184
) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.ServerConnection.c(ServerConnection.java
:81) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.MinecraftServer.v(MinecraftServer.java:7
31) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.DedicatedServer.v(DedicatedServer.java:2
84) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.MinecraftServer.u(MinecraftServer.java:5
84) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.MinecraftServer.run(MinecraftServer.java
:490) [spigot1543.jar:git-Spigot-1543]
        at net.minecraft.server.v1_7_R3.ThreadServerApplication.run(SourceFile:6
28) [spigot1543.jar:git-Spigot-1543]
Caused by: java.lang.NullPointerException
        at me.eml.friends.managers.FriendManager.listFriends(FriendManager.java:
165) ~[?:?]
        at me.eml.friends.commands._BASE.onCommand(_BASE.java:59) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spi
got1543.jar:git-Spigot-1543]
        ... 13 more