Help- Works on a loaclahost server but not on a Public Server

2011-11-13 17:51:54 [SEVERE] Could not load 'plugins\****.jar' in folder 'plugins':
java.lang.UnsupportedClassVersionError: com/***/***/*** : 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.findClass(PluginClassLoader.java:36)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:24)
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.java:170)
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:215)
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:136)
at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:136)
at org.bukkit.craftbukkit.CraftServer.<init>(CraftServer.java:112)
at net.minecraft.server.ServerConfigurationManager.<init>(ServerConfigurationManager.java:52)
at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:136)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:348)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)



i put *** just in the post because this is a private plugin

 

It means the version of Java on the public server is lower than the version the plugin was compiled with (and is on the local server).

Either update the public server's Java installation or develop the plugin for a lower version of Java.