1.17 support.

[XfedeX]

The plugin is not working on a 1.17 server.
This is log:

[15:04:33 INFO]:  [NetherView] Enabling NetherView v3.0.0
[15:04:34 WARN]: java.lang.ClassNotFoundException: net.minecraft.server.v1_17_R1.Entity
[15:04:34 WARN]:        at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:146)
[15:04:34 WARN]:        at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:103)
[15:04:34 WARN]:        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
[15:04:34 WARN]:        at java.base/java.lang.Class.forName0(Native Method)
[15:04:34 WARN]:        at java.base/java.lang.Class.forName(Class.java:375)
[15:04:34 WARN]:        at NetherView-v3.0.0.jar//me.gorgeousone.netherview.utils.NmsUtils.getNmsClass(NmsUtils.java:33)
[15:04:34 WARN]:        at NetherView-v3.0.0.jar//me.gorgeousone.netherview.utils.NmsUtils.<clinit>(NmsUtils.java:18)
[15:04:34 WARN]:        at NetherView-v3.0.0.jar//me.gorgeousone.netherview.packet.PacketHandler.createPacketsConstructors(PacketHandler.java:82)
[15:04:34 WARN]:        at NetherView-v3.0.0.jar//me.gorgeousone.netherview.packet.PacketHandler.<init>(PacketHandler.java:74)
[15:04:34 WARN]:        at NetherView-v3.0.0.jar//me.gorgeousone.netherview.NetherViewPlugin.onEnable(NetherViewPlugin.java:103)
[15:04:34 WARN]:        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:264)
[15:04:34 WARN]:        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:370)
[15:04:34 WARN]:        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:500)
[15:04:34 WARN]:        at org.bukkit.craftbukkit.v1_17_R1.CraftServer.enablePlugin(CraftServer.java:535)
[15:04:34 WARN]:        at org.bukkit.craftbukkit.v1_17_R1.CraftServer.enablePlugins(CraftServer.java:449)
[15:04:34 WARN]:        at net.minecraft.server.MinecraftServer.loadWorld(MinecraftServer.java:725)
[15:04:34 WARN]:        at net.minecraft.server.dedicated.DedicatedServer.init(DedicatedServer.java:306)
[15:04:34 WARN]:        at net.minecraft.server.MinecraftServer.x(MinecraftServer.java:1212)
[15:04:34 WARN]:        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:319)
[15:04:34 WARN]:        at java.base/java.lang.Thread.run(Thread.java:831)
[15:04:34 ERROR]: Error occurred while enabling NetherView v3.0.0 (Is it up to date?)
java.lang.RuntimeException: Failed to create packets constructors
        at me.gorgeousone.netherview.packet.PacketHandler.<init>(PacketHandler.java:76) ~[NetherView-v3.0.0.jar:?]
        at me.gorgeousone.netherview.NetherViewPlugin.onEnable(NetherViewPlugin.java:103) ~[NetherView-v3.0.0.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:264) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:370) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:500) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.craftbukkit.v1_17_R1.CraftServer.enablePlugin(CraftServer.java:535) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.craftbukkit.v1_17_R1.CraftServer.enablePlugins(CraftServer.java:449) ~[patched_1.17.1.jar:git-Paper-243]
        at net.minecraft.server.MinecraftServer.loadWorld(MinecraftServer.java:725) ~[patched_1.17.1.jar:git-Paper-243]
        at net.minecraft.server.dedicated.DedicatedServer.init(DedicatedServer.java:306) ~[patched_1.17.1.jar:git-Paper-243]
        at net.minecraft.server.MinecraftServer.x(MinecraftServer.java:1212) ~[patched_1.17.1.jar:git-Paper-243]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:319) ~[patched_1.17.1.jar:git-Paper-243]
        at java.lang.Thread.run(Thread.java:831) [?:?]
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_17_R1.Entity
        at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:146) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:103) ~[patched_1.17.1.jar:git-Paper-243]
        at java.lang.ClassLoader.loadClass(ClassLoader.java:519) ~[?:?]
        at java.lang.Class.forName0(Native Method) ~[?:?]
        at java.lang.Class.forName(Class.java:375) ~[?:?]
        at me.gorgeousone.netherview.utils.NmsUtils.getNmsClass(NmsUtils.java:33) ~[NetherView-v3.0.0.jar:?]
        at me.gorgeousone.netherview.packet.PacketHandler.createPacketsConstructors(PacketHandler.java:82) ~[NetherView-v3.0.0.jar:?]
        at me.gorgeousone.netherview.packet.PacketHandler.<init>(PacketHandler.java:74) ~[NetherView-v3.0.0.jar:?]
        ... 11 more
[15:04:34 INFO]: [NetherView] Disabling NetherView v3.0.0
[15:04:34 ERROR]: Error occurred while disabling NetherView v3.0.0 (Is it up to date?)
java.lang.NullPointerException: Cannot invoke "me.gorgeousone.netherview.handlers.PortalHandler.hasPortals(org.bukkit.World)" because "this.portalHandler" is null
        at me.gorgeousone.netherview.portal.PortalSerializer.savePortals(PortalSerializer.java:44) ~[NetherView-v3.0.0.jar:?]
        at me.gorgeousone.netherview.NetherViewPlugin.backupPortals(NetherViewPlugin.java:300) ~[NetherView-v3.0.0.jar:?]
        at me.gorgeousone.netherview.NetherViewPlugin.onDisable(NetherViewPlugin.java:173) ~[NetherView-v3.0.0.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:266) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:405) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:533) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:374) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:500) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.craftbukkit.v1_17_R1.CraftServer.enablePlugin(CraftServer.java:535) ~[patched_1.17.1.jar:git-Paper-243]
        at org.bukkit.craftbukkit.v1_17_R1.CraftServer.enablePlugins(CraftServer.java:449) ~[patched_1.17.1.jar:git-Paper-243]
        at net.minecraft.server.MinecraftServer.loadWorld(MinecraftServer.java:725) ~[patched_1.17.1.jar:git-Paper-243]
        at net.minecraft.server.dedicated.DedicatedServer.init(DedicatedServer.java:306) ~[patched_1.17.1.jar:git-Paper-243]
        at net.minecraft.server.MinecraftServer.x(MinecraftServer.java:1212) ~[patched_1.17.1.jar:git-Paper-243]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:319) ~[patched_1.17.1.jar:git-Paper-243]
        at java.lang.Thread.run(Thread.java:831) [?:?]