Error???

[LolYesLol]

This guy came on my server and started spamming: Give me $120 paypal and I wont crash your server.

I just booted + banned him. The server went offline, and I went to restart it, I got an error, it compiles fine, just cant run it.

This is the error:

Exception in thread "main" java.lang.UnsupportedClassVersionError: server : Unsu
pported major.minor version 8242.8224
        at java.lang.ClassLoader.defineClass1(Native Method)
        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$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)
Press any key to continue . . .

Please help.