Bukkit

What steps will reproduce the problem?
1.Start 1.8.8 server Spigot
2.
3.

What is the expected output? What do you see instead?
Expect server to run.
Server runs but RPGSkill could not start.

What version of the product are you using?
Latest (1.4.0) RPGSkill
1.8.8 Spigot

Do you have an error log of what happened?
30.09 22:14:57 [Server] INFO at java.lang.Thread.run(Thread.java:745) [?:1.7.0_79]
30.09 22:14:57 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:524) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:263) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.a(MinecraftServer.java:333) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.k(MinecraftServer.java:378) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.s(MinecraftServer.java:414) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at org.bukkit.craftbukkit.v1_8_R3.CraftServer.enablePlugins(CraftServer.java:316) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugin(CraftServer.java:356) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340) [spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot18.jar:git-Spigot-f94fe8f-d27e6d0]
30.09 22:14:57 [Server] INFO at me.deadlyscone.main.RPGSkills.onEnable(RPGSkills.java:147) ~[?:?]
30.09 22:14:57 [Server] INFO at me.deadlyscone.main.ConfigParser.scanFiles(ConfigParser.java:49) ~[?:?]
30.09 22:14:57 [Server] INFO java.lang.NoSuchMethodError: java.nio.file.Files.readAllLines(Ljava/nio/file/Path;)Ljava/util/List;
30.09 22:14:57 [Server] ERROR Error occurred while enabling RPGSkills v3.4.0b (Is it up to date?)

Please provide any additional information below.
It runs on 1.8.7 but in this version breed (cows/sheep as far as i know) will almost never give xp for breeding. (1 in 50 will give xp)

Ingame the /rs command would give responds like normal but when geting skill info it would give a internal error.

Put server back to 1.8.7 and it works again.