What's happening?

I tried to create a plugin. The server generated such an error. What to do?

[17:12:48 ERROR]: Could not load 'plugins\Plugman1.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: klaster/main/Plugman has been compiled by a more recent version of the Java Runtime (class file version 57.0), this version of the Java Runtime only recognizes class file versions up to 52.0
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:133) ~[s.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:327) ~[s.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:248) [s.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.loadPlugins(CraftServer.java:305) [s.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:205) [s.jar:git-Spigot-dcd1643-e60fc34]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:545) [s.jar:git-Spigot-dcd1643-e60fc34]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_241]
Caused by: java.lang.UnsupportedClassVersionError: klaster/main/Plugman has been compiled by a more recent version of the Java Runtime (class file version 57.0), this version of the Java Runtime only recognizes class file versions up to 52.0
at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.8.0_241]
at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.8.0_241]
at java.security.SecureClassLoader.defineClass(Unknown Source) ~[?:1.8.0_241]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:148) ~[s.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:100) ~[s.jar:git-Spigot-dcd1643-e60fc34]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_241]
at java.lang.Class.forName0(Native Method) ~[?:1.8.0_241]
at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_241]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:78) ~[s.jar:git-Spigot-dcd1643-e60fc34]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:129) ~[s.jar:git-Spigot-dcd1643-e60fc34]
... 6 more

 

@timtower

I tried on version 13 and 8. Everything is in vain.

 

@timtower

Yes, on mine.

 

@timtower
java version "1.8.0_241"
Java(TM) SE Runtime Environment (build 1.8.0_241-b07)
Java HotSpot(TM) Client VM (build 25.241-b07, mixed mode, sharing)

 

@timtower Let's i try and tag you after, ok?

@timtower

I tried with 1.8 and it worked. Thanks.

EDIT by Moderator: merged posts, please use the edit button instead of double posting.