Help with Java for minecraft

[22:09:18] [Server thread/INFO]: Starting minecraft server version 1.8.8
[22:09:18] [Server thread/INFO]: Loading properties
[22:09:18] [Server thread/INFO]: Default game type: SURVIVAL
[22:09:18] [Server thread/INFO]: Generating keypair
[22:09:18] [Server thread/INFO]: Starting Minecraft server on *:25565
[22:09:18] [Server thread/INFO]: Using default channel type
[22:09:19] [Server thread/INFO]: This server is running CraftBukkit version git-Bukkit-880a532 (MC: 1.8.8) (Implementing API version 1.8.8-R0.1-SNAPSHOT)
[22:09:19] [Server thread/ERROR]: Could not load 'plugins\Cows.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: Cannot find main class `me.danielporsh911.Cows'
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:42) ~[craftbukkit.jar:git-Bukkit-880a532]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:129) ~[craftbukkit.jar:git-Bukkit-880a532]
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:328) ~[craftbukkit.jar:git-Bukkit-880a532]
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [craftbukkit.jar:git-Bukkit-880a532]
	at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugins(CraftServer.java:289) [craftbukkit.jar:git-Bukkit-880a532]
	at org.bukkit.craftbukkit.v1_8_R3.CraftServer.<init>(CraftServer.java:251) [craftbukkit.jar:git-Bukkit-880a532]
	at net.minecraft.server.v1_8_R3.PlayerList.<init>(PlayerList.java:69) [craftbukkit.jar:git-Bukkit-880a532]
	at net.minecraft.server.v1_8_R3.DedicatedPlayerList.<init>(SourceFile:14) [craftbukkit.jar:git-Bukkit-880a532]
	at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:179) [craftbukkit.jar:git-Bukkit-880a532]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:503) [craftbukkit.jar:git-Bukkit-880a532]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_51]
Caused by: java.lang.ClassNotFoundException: me.danielporsh911.Cows
	at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.8.0_51]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:77) ~[craftbukkit.jar:git-Bukkit-880a532]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62) ~[craftbukkit.jar:git-Bukkit-880a532]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_51]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_51]
	at java.lang.Class.forName0(Native Method) ~[?:1.8.0_51]
	at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_51]
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:40) ~[craftbukkit.jar:git-Bukkit-880a532]
	... 10 more
[22:09:19] [Server thread/WARN]: **** SERVER IS RUNNING IN OFFLINE/INSECURE MODE!
[22:09:19] [Server thread/WARN]: The server will make no attempt to authenticate usernames. Beware.
[22:09:19] [Server thread/WARN]: While this makes the game possible to play without internet access, it also opens up the ability for hackers to connect with any username they choose.
[22:09:19] [Server thread/WARN]: To change this, set "online-mode" to "true" in the server.properties file.
[22:09:19] [Server thread/INFO]: Preparing level "world"
[22:09:19] [Server thread/INFO]: Preparing start region for level 0 (Seed: -1740568274544760765)
[22:09:20] [Server thread/INFO]: Preparing start region for level 1 (Seed: -1740568274544760765)
[22:09:20] [Server thread/INFO]: Preparing start region for level 2 (Seed: -1740568274544760765)
[22:09:21] [Server thread/INFO]: Server permissions file permissions.yml is empty, ignoring it
[22:09:21] [Server thread/INFO]: Done (1.999s)! For help, type "help" or "?"
[22:09:53] [Server thread/INFO]: Stopping the server
[22:09:53] [Server thread/INFO]: Stopping server
[22:09:53] [Server thread/INFO]: Saving players
[22:09:53] [Server thread/INFO]: Saving worlds
[22:09:53] [Server thread/INFO]: Saving chunks for level 'world'/Overworld
[22:09:54] [Server thread/INFO]: Saving chunks for level 'world_nether'/Nether
[22:09:54] [Server thread/INFO]: Saving chunks for level 'world_the_end'/The End