6d026765_Plugin_YAML___BukkitWiki_Attributes_Notes
[Attribute] main [Required] yes [Description] Points to the class that extends JavaPlugin [Example] main: org.bukkit.plugin.MyPlugin [Notes] 
Note that this must contain the full namespace including the class file itself. If your namespace is org.bukkit.plugin, and your class file is called MyPlugin then this must be org.bukkit.plugin.MyPlugin
Plugin YAML - BukkitWiki
Notes