Bukkit

What steps will reproduce the problem?
1. I put the jar in the plugins folder
2. I opened my server
3. *crashed*

What is the expected output? What do you see instead?

I expected it to work but it didnt :l

What version of the product are you using?

I am using git-Spigot-1135 1.6.4

Do you have an error log of what happened?

10:12:11 [SEVERE] Could not load 'plugins\InterestingFish_v1.1.jar' in folder 'p
lugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError
: net/shotbow/interestingfish/InterestingFish : Unsupported major.minor version
51.0
        at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.j
ava:184)
        at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.
java:306)
        at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager
.java:230)
        at org.bukkit.craftbukkit.v1_6_R3.CraftServer.loadPlugins(CraftServer.ja
va:245)
        at org.bukkit.craftbukkit.v1_6_R3.CraftServer.reload(CraftServer.java:61
6)
        at org.bukkit.Bukkit.reload(Bukkit.java:277)
        at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:
24)
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:19
2)
        at org.bukkit.craftbukkit.v1_6_R3.CraftServer.dispatchCommand(CraftServe
r.java:532)
        at org.bukkit.craftbukkit.v1_6_R3.CraftServer.dispatchServerCommand(Craf
tServer.java:519)
        at net.minecraft.server.v1_6_R3.DedicatedServer.as(DedicatedServer.java:
276)
        at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:2
41)
        at net.minecraft.server.v1_6_R3.MinecraftServer.s(MinecraftServer.java:4
83)
        at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java
:415)
        at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:5
83)
Caused by: java.lang.UnsupportedClassVersionError: net/shotbow/interestingfish/I
nterestingFish : Unsupported major.minor version 51.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClassCond(Unknown Source)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$000(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader
.java:80)
        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.
java:53)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Unknown Source)
        at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.j
ava:173)
        ... 14 more

Please provide any additional information below.

Please help!