Fails to load

[23:28:57] [Server thread/ERROR]: Could not load 'plugins/Lukkit-2.0-beta.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoSuchMethodError: com.google.common.collect.Sets$SetView.iterator()Lcom/google/common/collect/UnmodifiableIterator;
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[minecraft_server.jar:git-Spigot-21fe707-e1ebe52]
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:329) ~[minecraft_server.jar:git-Spigot-21fe707-e1ebe52]
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [minecraft_server.jar:git-Spigot-21fe707-e1ebe52]
	at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugins(CraftServer.java:292) [minecraft_server.jar:git-Spigot-21fe707-e1ebe52]
	at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:198) [minecraft_server.jar:git-Spigot-21fe707-e1ebe52]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:525) [minecraft_server.jar:git-Spigot-21fe707-e1ebe52]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]
Caused by: java.lang.NoSuchMethodError: com.google.common.collect.Sets$SetView.iterator()Lcom/google/common/collect/UnmodifiableIterator;
	at org.reflections.Reflections.expandSuperTypes(Reflections.java:380) ~[?:?]
	at org.reflections.Reflections.(Reflections.java:126) ~[?:?]
	at org.reflections.Reflections.(Reflections.java:168) ~[?:?]
	at org.reflections.Reflections.(Reflections.java:141) ~[?:?]
	at nz.co.jammehcow.lukkit.Main.(Main.java:57) ~[?:?]
	at java.lang.Class.forName0(Native Method) ~[?:1.8.0_171]
	at java.lang.Class.forName(Class.java:348) ~[?:1.8.0_171]
	at org.bukkit.plugin.java.PluginClassLoader.(PluginClassLoader.java:64) ~[minecraft_server.jar:git-Spigot-21fe707-e1ebe52]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[minecraft_server.jar:git-Spigot-21fe707-e1ebe52]
	... 6 more