[ERROR] Could not load 'plugins/EchoPunishments.jar' in folder 'plugins'

org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: JVMCFRE003 bad major version; class=me/sirbikesalot/EchoPunishments/Main, offset=6

at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:329) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugins(CraftServer.java:292) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:198) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:525) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at java.lang.Thread.run(Thread.java:813) [?:1.8.0_212]

Caused by: java.lang.UnsupportedClassVersionError: JVMCFRE003 bad major version; class=me/sirbikesalot/EchoPunishments/Main, offset=6

at java.lang.ClassLoader.defineClassImpl(Native Method) ~[?:1.8.0_212]

at java.lang.ClassLoader.defineClassInternal(ClassLoader.java:391) ~[?:1.8.0_212]

at java.lang.ClassLoader.defineClass(ClassLoader.java:360) ~[?:1.8.0_212]

at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[?:1.8.0_212]

at java.net.URLClassLoader.defineClass(URLClassLoader.java:682) ~[?:1.8.0_212]

at java.net.URLClassLoader.access$400(URLClassLoader.java:89) ~[?:1.8.0_212]

at java.net.URLClassLoader$ClassFinder.run(URLClassLoader.java:1086) ~[?:1.8.0_212]

at java.security.AccessController.doPrivileged(AccessController.java:739) ~[?:1.8.0_212]

at java.net.URLClassLoader.findClass(URLClassLoader.java:589) ~[?:1.8.0_212]

at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:101) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at java.lang.ClassLoader.loadClassHelper(ClassLoader.java:946) ~[?:1.8.0_212]

at java.lang.ClassLoader.loadClass(ClassLoader.java:891) ~[?:1.8.0_212]

at java.lang.ClassLoader.loadClass(ClassLoader.java:874) ~[?:1.8.0_212]

at java.lang.Class.forNameImpl(Native Method) ~[?:1.8.0_212]

at java.lang.Class.forName(Class.java:403) ~[?:1.8.0_212]

at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:64) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]