Solved java.lang.UnsupportedClassVersionError

Hello everyone.

So i got my localhost server and a server hosted online by a hosting company.
I created a plugin, it works fine with the localhost server, but not with the public one.
here is the console error:

Code:

31.08 23:57:27 [Server] INFO at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:64) ~[spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at java.lang.Class.forName(Class.java:270) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.lang.Class.forName0(Native Method) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.lang.ClassLoader.loadClass(ClassLoader.java:358) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.lang.ClassLoader.loadClass(ClassLoader.java:425) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86) ~[spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:101) ~[spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at java.net.URLClassLoader.findClass(URLClassLoader.java:354) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.security.AccessController.doPrivileged(Native Method) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.net.URLClassLoader$1.run(URLClassLoader.java:355) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.net.URLClassLoader$1.run(URLClassLoader.java:361) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.net.URLClassLoader.access$100(URLClassLoader.java:71) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.net.URLClassLoader.defineClass(URLClassLoader.java:449) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.lang.ClassLoader.defineClass(ClassLoader.java:800) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.7.0_55]
31.08 23:57:27 [Server] INFO Caused by: java.lang.UnsupportedClassVersionError: me/karsten/tfk/Main : Unsupported major.minor version 52.0
31.08 23:57:27 [Server] INFO at java.lang.Thread.run(Thread.java:744) [?:1.7.0_55]
31.08 23:57:27 [Server] INFO at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:505) [spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at net.minecraft.server.v1_8_R1.DedicatedServer.init(DedicatedServer.java:152) [spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at org.bukkit.craftbukkit.v1_8_R1.CraftServer.loadPlugins(CraftServer.java:291) [spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:329) ~[spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[spigot.jar:git-Spigot-c3c767f-33d5de3]
31.08 23:57:27 [Server] INFO org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: me/karsten/tfk/Main : Unsupported major.minor version 52.0
31.08 23:57:27 [Server] INFO [23:57:27 ERROR]: Could not load 'plugins/TheFreeKingdom.jar' in folder 'plugins'

Thanks

 

52 = java 1.8 (a.k.a Java 8)
I am assuming you are running Java 1.8 on your PC, and the server host is (probably) using Java 1.7 (a.k.a Java 7)

 

To reiterate what he's saying here. You are compiling your plugin using Java 8 and the server is using Java 7. Simply change your JRE to Java 7 and you'll be good to go

 

Thanks, I'll try that

I tried this, I tried java 6, 7 and 8. it still gives the message.... I don't get it

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Wrong. JRE is the JavaRuntimeEnvironment (for executing the code). JDK is the JavaDevelopementKit (for compiling the code). So he needs to change his JDK

 

Nope, I'm sorry, my code was just wrong xD
@travja was right, it wasn't the JDK but the JRE.

Thank you all!

- SOLVED