Bukkit

23:03:03 CONSOLE:[SEVERE] org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: com/pl/MYCRAFTisbest/RealisticChat/RealisticChat : Unsupported major.minor version 51.0
23:03:03 CONSOLE:[SEVERE] at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:154)
23:03:03 CONSOLE:[SEVERE] at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
23:03:03 CONSOLE:[SEVERE] at net.skycraftmc.PluginManager.PluginControl.loadPlugin(PluginControl.java:72)
23:03:03 CONSOLE:[SEVERE] at net.skycraftmc.PluginManager.PluginManagerPlugin.onCommand(PluginManagerPlugin.java:206)
23:03:03 CONSOLE:[SEVERE] at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
23:03:03 CONSOLE:[SEVERE] at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:186)
23:03:03 CONSOLE:[SEVERE] at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:502)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:985)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:903)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:858)
23:03:03 CONSOLE:[SEVERE] at net.minecraftserverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:124)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:44)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.NetworkManager.b(NetworkManager.java:290)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.ServerConnection.b(SourceFile:39)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.DedicatedServerConnection.b(SourceFile:30)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.NetServerHandler.d(NetServerHandler.java:113)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:595)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:222)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:426)
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.ThreadServerApplication.run(SourceFile:856)
23:03:03 CONSOLE:[SEVERE] Caused by: java.lang.UnsupportedClassVersionError: com/pl/MYCRAFTisbest/RealisticChat/RealisticChat : Unsupported major.minor version 51.0
23:03:03 CONSOLE:[SEVERE] at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:493)
23:03:03 CONSOLE:[SEVERE] at java.lang.ClassLoader.defineClass1(Native Method)
23:03:03 CONSOLE:[SEVERE] at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
23:03:03 CONSOLE:[SEVERE] at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
23:03:03 CONSOLE:[SEVERE] at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
23:03:03 CONSOLE:[SEVERE] at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
23:03:03 CONSOLE:[SEVERE] at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
23:03:03 CONSOLE:[SEVERE] at java.security.AccessController.doPrivileged(Native Method)
23:03:03 CONSOLE:[SEVERE] at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
23:03:03 CONSOLE:[SEVERE] at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
23:03:03 CONSOLE:[SEVERE] at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
23:03:03 CONSOLE:[SEVERE] at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:29)
23:03:03 CONSOLE:[SEVERE] at java.lang.Class.forName(Class.java:247)
23:03:03 CONSOLE:[SEVERE] at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:44)
23:03:03 CONSOLE:[SEVERE] at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
23:03:03 CONSOLE:[SEVERE] at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:143)
23:03:03 CONSOLE.[SEVERE] ... 20 more
23:03:03 CONSOLE:[SEVERE] at java.lang.Class.forName0(Native Method)