0x8 Error

[dasekte87]

I downloaded a nulled TEShop plugin. I have put it in my plugins folder and ran my server. At the time the server is about to be done loading, TEShop tries to go enable. Then it gone error and shown this message, then shuts down my server.

[15:08:15 INFO]: [TEShop] Enabling TEShop v2.0.4
[15:08:15 WARN]: java.lang.ClassNotFoundException: sun.reflect.ConstantPool
[15:08:15 WARN]: at java.base/java.net.URLClassLoader.findClass(Unknown Source)
[15:08:15 WARN]: at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:77)
[15:08:15 WARN]: at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62)
[15:08:15 WARN]: at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
[15:08:15 WARN]: at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
[15:08:15 WARN]: at java.base/java.lang.Class.forName0(Native Method)
[15:08:15 WARN]: at java.base/java.lang.Class.forName(Unknown Source)
[15:08:15 WARN]: at com.gianscode.teshop.Main.????????(Main.java)
[15:08:15 WARN]: at java.base/java.lang.invoke.CallSite.makeSite(Unknown Source)
[15:08:15 WARN]: at java.base/java.lang.invoke.MethodHandleNatives.linkCallSiteImpl(Unknown Source)
[15:08:15 WARN]: at java.base/java.lang.invoke.MethodHandleNatives.linkCallSite(Unknown Source)
[15:08:15 WARN]: at com.gianscode.teshop.Main.onEnable(Main.java:30)
[15:08:15 WARN]: at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:264)
[15:08:15 WARN]: at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:329)
[15:08:15 WARN]: at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:402)
[15:08:15 WARN]: at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugin(CraftServer.java:368)
[15:08:15 WARN]: at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugins(CraftServer.java:329)
[15:08:15 WARN]: at net.minecraft.server.v1_12_R1.MinecraftServer.t(MinecraftServer.java:412)
[15:08:15 WARN]: at net.minecraft.server.v1_12_R1.MinecraftServer.l(MinecraftServer.java:373)
[15:08:15 WARN]: at net.minecraft.server.v1_12_R1.MinecraftServer.a(MinecraftServer.java:328)
[15:08:15 WARN]: at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:248)
[15:08:15 WARN]: at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:522)
[15:08:15 WARN]: at java.base/java.lang.Thread.run(Unknown Source)
[15:08:15 INFO]: [TEShop-4286] An unknown error has occurred. Please contact DirectLeaks (Error: 0x8, Your java version is not supported yet, 9.0.1)
[15:08:15 INFO]: [TEShop-4286] Website: https://directleaks.net

At this part is where I am confused:
[15:08:15 INFO]: [TEShop-4286] An unknown error has occurred. Please contact DirectLeaks (Error: 0x8, Your java version is not supported yet, 9.0.1)

What should I do? Update/Downgrade my Java to some kind of Java 9.0.1 or I needed to update my Java to a higher version?

Please help.

 

[Titan Nodes]

Error: 0x8, Your java version is not supported yet, 9.0.1
Change your server's java version.

 

[dasekte87]

Error: 0x8, Your java version is not supported yet, 9.0.1
Change your server's java version.

How?