Bukkit

What steps will reproduce the problem?
1. Creating a server using this plugin

What is the expected output? What do you see instead?
I expect to be able to use the plugin, but instead the plugin won't load.

What version of the product are you using?
1.0.0

Do you have an error log of what happened?
20:10:14 [SEVERE] Could not load 'plugins/SimpleProjectile.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: simpleprojectile/SimpleProjectile : Unsupported major.minor version 51.0
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184)
    at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
    at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
    at org.bukkit.craftbukkit.v1_4_6.CraftServer.loadPlugins(CraftServer.java:239)
    at org.bukkit.craftbukkit.v1_4_6.CraftServer.<init>(CraftServer.java:217)
    at net.minecraft.server.v1_4_6.PlayerList.<init>(PlayerList.java:52)
    at net.minecraft.server.v1_4_6.DedicatedPlayerList.<init>(SourceFile:11)
    at net.minecraft.server.v1_4_6.DedicatedServer.init(DedicatedServer.java:104)
    at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:399)
    at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.UnsupportedClassVersionError: simpleprojectile/SimpleProjectile : Unsupported major.minor version 51.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
    at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    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(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:247)
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173)
    ... 9 more

Please provide any additional information below.
I tried using it with lots of plugins and then with only PowerTool.

This is because this plugin was compiled with JDK7.  I highly recommend that you get Java 7 on your server, but I will upload a Java 6 version.

EDIT: I'm unable to find a JDK for Java 6.  Please do update your server to Java 7 as there are a number of viruses available for Java 6 that have been fixed in 7.

@ReaperOftheMine: Go

I downloaded Java 7 onto my computer, I still get an error.

15:42:09 [SEVERE] Could not load 'plugins/SimpleProjectile.jar' in folder 'plugins' org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: simpleprojectile/SimpleProjectile : Unsupported major.minor version 51.0 at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184) at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305) at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230) at org.bukkit.craftbukkit.v1_4_6.CraftServer.loadPlugins(CraftServer.java:239) at org.bukkit.craftbukkit.v1_4_6.CraftServer.<init>(CraftServer.java:217) at net.minecraft.server.v1_4_6.PlayerList.<init>(PlayerList.java:52) at net.minecraft.server.v1_4_6.DedicatedPlayerList.<init>(SourceFile:11) at net.minecraft.server.v1_4_6.DedicatedServer.init(DedicatedServer.java:104) at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:399) at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849) Caused by: java.lang.UnsupportedClassVersionError: simpleprojectile/SimpleProjectile : Unsupported major.minor version 51.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631) at java.lang.ClassLoader.defineClass(ClassLoader.java:615) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) at java.net.URLClassLoader.access$000(URLClassLoader.java:58) at java.net.URLClassLoader$1.run(URLClassLoader.java:197) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) 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(ClassLoader.java:306) at java.lang.ClassLoader.loadClass(ClassLoader.java:247) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:247) at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173) ... 9 more

You mentioned installing Java 7 onto the server, is that different then installing it on to the computer?

@Kitten_Tails: Go

Yes. Please install Java 7 on whatever machine you are running the server on.