Error

[16:19:33 ERROR]: Could not load 'plugins/idk.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: Abnormal plugin type
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:56) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:127) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:328) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at org.bukkit.craftbukkit.v1_7_R4.CraftServer.loadPlugins(CraftServer.java:364) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at org.bukkit.craftbukkit.v1_7_R4.CraftServer.<init>(CraftServer.java:326) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at net.minecraft.server.v1_7_R4.PlayerList.<init>(PlayerList.java:68) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at net.minecraft.server.v1_7_R4.DedicatedPlayerList.<init>(SourceFile:14) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at net.minecraft.server.v1_7_R4.DedicatedServer.init(DedicatedServer.java:133) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:436) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
	at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]
Caused by: java.lang.InstantiationException: me.eightbitfusion.TierApples
	at java.lang.Class.newInstance0(Class.java:342) ~[?:1.6.0_65]
	at java.lang.Class.newInstance(Class.java:310) ~[?:1.6.0_65]
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:52) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-14-gd373bc2-b3103jnks]