Bukkit

What is the task?
When disabling the plugin.
Please provide any additional information below.

This is the error>

[19:44:20] [Server thread/ERROR]: Error occurred while disabling Compass v1.0 (Is it up to date?)
        java.lang.IllegalMonitorStateException
    at java.lang.Object.wait(Native Method) ~[?:1.8.0_31]
    at me.promckingz.compass.Main.onDisable(Main.java:38) ~[?:?]
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:323) ~[spigot.jar:git-Spigot-8a983f9-9ae3381]
    at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:359) [spigot.jar:git-Spigot-8a983f9-9ae3381]
    at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:424) [spigot.jar:git-Spigot-8a983f9-9ae3381]
    at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:417) [spigot.jar:git-Spigot-8a983f9-9ae3381]
    at org.bukkit.craftbukkit.v1_8_R1.CraftServer.disablePlugins(CraftServer.java:335) [spigot.jar:git-Spigot-8a983f9-9ae3381]
    at net.minecraft.server.v1_8_R1.MinecraftServer.stop(MinecraftServer.java:430) [spigot.jar:git-Spigot-8a983f9-9ae3381]
    at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:561) [spigot.jar:git-Spigot-8a983f9-9ae3381]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_31]