: Could not load 'plugins/BossMessage.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: net/pixelizedmc/bossmessage/Main : Unsupported major.minor version 51.0
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot.jar:git-Spigot-1483]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java

29) ~[spigot.jar:git-Spigot-1483]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [spigot.jar:git-Spigot-1483]
at org.bukkit.craftbukkit.v1_7_R3.CraftServer.loadPlugins(CraftServer.java

58) [spigot.jar:git-Spigot-1483]
at net.minecraft.server.v1_7_R3.DedicatedServer.init(DedicatedServer.java:135) [spigot.jar:git-Spigot-1483]
at net.minecraft.server.v1_7_R3.MinecraftServer.run(MinecraftServer.java:457) [spigot.jar:git-Spigot-1483]
at net.minecraft.server.v1_7_R3.ThreadServerApplication.run(SourceFile:628) [spigot.jar:git-Spigot-1483]
Caused by: java.lang.UnsupportedClassVersionError: net/pixelizedmc/bossmessage/Main : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.6.0_31]
at java.lang.ClassLoader.defineClass(ClassLoader.java:643) ~[?:1.6.0_31]
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[?:1.6.0_31]
at java.net.URLClassLoader.defineClass(URLClassLoader.java:277) ~[?:1.6.0_31]
at java.net.URLClassLoader.access$000(URLClassLoader.java:73) ~[?:1.6.0_31]
at java.net.URLClassLoader$1.run(URLClassLoader.java:212) ~[?:1.6.0_31]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.6.0_31]
at java.net.URLClassLoader.findClass(URLClassLoader.java:205) ~[?:1.6.0_31]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:77) ~[spigot.jar:git-Spigot-1483]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62) ~[spigot.jar:git-Spigot-1483]
at java.lang.ClassLoader.loadClass(ClassLoader.java

23) ~[?:1.6.0_31]
at java.lang.ClassLoader.loadClass(ClassLoader.java:268) ~[?:1.6.0_31]
at java.lang.Class.forName0(Native Method) ~[?:1.6.0_31]
at java.lang.Class.forName(Class.java:270) ~[?:1.6.0_31]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:40) ~[spigot.jar:git-Spigot-1483]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:127) ~[spigot.jar:git-Spigot-1483]
... 6 more
]