Plugin Error

I was trying to upload a plugin {UniqueMOTD} to my server but when i tried loading it on the server thhis came up...


[12:40:15 INFO]: This server is running CraftBukkit version git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks (MC: 1.7.9) (Implementing API version 1.7.9-R0.2)
[12:40:16 ERROR]: Could not load 'plugins/UniqueMOTD.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: me/treblue/uniquemotd/UniqueMOTD : Unsupported major.minor version 51.0
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:328) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at org.bukkit.craftbukkit.v1_7_R3.CraftServer.loadPlugins(CraftServer.java:355) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at org.bukkit.craftbukkit.v1_7_R3.CraftServer.<init>(CraftServer.java:317) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at net.minecraft.server.v1_7_R3.PlayerList.<init>(PlayerList.java:68) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at net.minecraft.server.v1_7_R3.DedicatedPlayerList.<init>(SourceFile:14) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at net.minecraft.server.v1_7_R3.DedicatedServer.init(DedicatedServer.java:126) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at net.minecraft.server.v1_7_R3.MinecraftServer.run(MinecraftServer.java:436) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at net.minecraft.server.v1_7_R3.ThreadServerApplication.run(SourceFile:628) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
Caused by: java.lang.UnsupportedClassVersionError: me/treblue/uniquemotd/UniqueMOTD : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.6.0_65]
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637) ~[?:1.6.0_65]
at java.lang.ClassLoader.defineClass(ClassLoader.java:621) ~[?:1.6.0_65]
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) ~[?:1.6.0_65]
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) ~[?:1.6.0_65]
at java.net.URLClassLoader.access$000(URLClassLoader.java:58) ~[?:1.6.0_65]
at java.net.URLClassLoader$1.run(URLClassLoader.java:197) ~[?:1.6.0_65]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.6.0_65]
at java.net.URLClassLoader.findClass(URLClassLoader.java:190) ~[?:1.6.0_65]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:77) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at java.lang.ClassLoader.loadClass(ClassLoader.java:306) ~[?:1.6.0_65]
at java.lang.ClassLoader.loadClass(ClassLoader.java:247) ~[?:1.6.0_65]
at java.lang.Class.forName0(Native Method) ~[?:1.6.0_65]
at java.lang.Class.forName(Class.java:249) ~[?:1.6.0_65]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:40) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:127) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-10-g8688bd4-b3092jnks]
... 9 more


This has happened to me with a lot of plugins and I dont know why!

 

I think it's because the version is 51.0. It may be too high? Idk, just a guess

 

Plugin requires Java 7 while server uses java 6.

 

I have Java 7 but it still happens