Plugin can't find ClassFile specified in plugin.yml

Hey Bukkit,
Alright so I just got into development, and this is my first plugin.
It's a plugin to greet new joiners, and I have the folders like so:
src/fj/FirstJoin.class

This is my Plugin.yml
name: FirstJoin
main: fj.FirstJoin
version: 1.0
author: Qwahchees

What's going on?
I get this:
22:22:44 [SEVERE] Could not load 'plugins\FirstJoin.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.ClassCastException: class f
.FirstJoin
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.
ava:150)
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager
java:305)
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManage
.java:230)
at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:207)
at org.bukkit.craftbukkit.CraftServer.<init>(CraftServer.java:183)
at net.minecraft.server.ServerConfigurationManager.<init>(ServerConfigu
ationManager.java:53)
at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:156)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:490)
Caused by: java.lang.ClassCastException: class fj.FirstJoin
at java.lang.Class.asSubclass(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.
ava:140)
... 8 more

Nevermind, /void this I found the problem.

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Just a friendly reminder to rename your topics with "[Solved]" once a solution is found, as a courtesy.

 

Can you share the solution. Im having a similar issue :S
Thanks, Ismaw34

 

I bet you need to extend JavaPlugin

 

You have to put the full path in 'main:' in your plugin.yml, e.g. 'main: my.package.MyPlugin' where MyPlugin is the main class whose package definition is 'package my.package;'

 

Hello, i have extended the class:

Code:

public class Test extends JavaPlugin implements Listener {

And the main package its fine:

Code:

main: test.plugin.Test

Assuming is src/test/plugin/Test.class

Thanks, Ismaw34

Added the bukkit.jar, all the net and org things.
And its working again... Thanks, Ismaw34