[22:06:55 ERROR]: Could not load 'plugins\FistPlugin.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError
: org/tutorial/fistplugin/FistPlugin has been compiled by a more recent version
of the Java Runtime (class file version 58.0), this version of the Java Runtime
only recognizes class file versions up to 52.0
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.j
ava:133) ~[Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.
java

27) ~[Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager
.java:248) [Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.loadPlugins(CraftServer.j
ava

05) [Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.ja
va:205) [Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.jav
a:545) [Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_261]
Caused by: java.lang.UnsupportedClassVersionError: org/tutorial/fistplugin/FistP
lugin has been compiled by a more recent version of the Java Runtime (class file
version 58.0), this version of the Java Runtime only recognizes class file vers
ions up to 52.0
at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.8.0_261]
at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.8.0_261]
at java.security.SecureClassLoader.defineClass(Unknown Source) ~[?:1.8.0
_261]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.
java:148) ~[Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.
java:100) ~[Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_261]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_261]
at java.lang.Class.forName0(Native Method) ~[?:1.8.0_261]
at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_261]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.jav
a:78) ~[Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.j
ava:129) ~[Spigot-1.12.2.jar:git-Spigot-dcd1643-e60fc34]
... 6 more