How to read error log...?

Hey, i have been getting this error and i just want to know how to read error logs to be able to fix my coding.
Heres the log:

Code:

[SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'welcome' in plugin LBWelcome v1.0
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:185)
    at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:502)
    at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:917)
    at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:835)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:812)
    at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:44)
    at net.minecraft.server.NetworkManager.b(NetworkManager.java:290)
    at net.minecraft.server.NetServerHandler.d(NetServerHandler.java:112)
    at net.minecraft.server.ServerConnection.b(SourceFile:39)
    at net.minecraft.server.DedicatedServerConnection.b(SourceFile:30)
    at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:595)
    at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:222)
    at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:493)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:426)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:856)
Caused by: java.lang.NullPointerException
    at net.skydevs.src.LBWelcome.onCommand(LBWelcome.java:34)
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
    ... 15 more

 

The link to your answer is a sticky in this category...
How to read stack-traces, and troubleshoot your own plugins (by yourself)

 

Oh, i dint see that, thanks