[19:33:34 INFO]: [ProtocolLib] Enabling ProtocolLib v5.0.0-SNAPSHOT-636
[19:33:34 INFO]: Error Cannot enable ProtocolLib. (java.lang.IllegalStateException: Unable to access field private final java.util.List net.minecraft.server.v1_16_R3.ServerConnection.listeningChannels) occurred in ProtocolLib v5.0.0-SNAPSHOT-636.
[19:33:34 ERROR]: [ProtocolLib] INTERNAL ERROR: Cannot enable ProtocolLib.
If this problem hasn't already been reported, please open a ticket
at https://github.com/dmulloy2/ProtocolLib/issues with the following data:
Stack Trace:
java.lang.IllegalStateException: Unable to access field private final java.util.List net.minecraft.server.v1_16_R3.ServerConnection.listeningChannels
at com.comphenix.protocol.reflect.accessors.MethodHandleHelper.getFieldAccessor(MethodHandleHelper.java:119)
at com.comphenix.protocol.reflect.accessors.Accessors.getFieldAccessor(Accessors.java:84)
at com.comphenix.protocol.injector.netty.manager.NetworkManagerInjector.inject(NetworkManagerInjector.java:203)
at com.comphenix.protocol.injector.PacketFilterManager.registerEvents(PacketFilterManager.java:458)
at com.comphenix.protocol.ProtocolLib.onEnable(ProtocolLib.java:336)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:263)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:370)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:500)
at org.bukkit.craftbukkit.v1_16_R3.CraftServer.enablePlugin(CraftServer.java:518)
at org.bukkit.craftbukkit.v1_16_R3.CraftServer.enablePlugins(CraftServer.java:432)
at net.minecraft.server.v1_16_R3.DedicatedServer.init(DedicatedServer.java:280)
at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1074)
at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:293)
at net.minecraft.server.v1_16_R3.MinecraftServer$$Lambda$3175/0x00000000a5e7d7d0.run(Unknown Source)
at java.base/java.lang.Thread.run(Thread.java:883)
Caused by: java.lang.IllegalAccessException: illegal setter on final field
at java.base/java.lang.invoke.MethodHandles$Lookup.findSetter(MethodHandles.java:1084)
at com.comphenix.protocol.reflect.accessors.MethodHandleHelper.getFieldAccessor(MethodHandleHelper.java:96)
... 14 more
Dump:
manager:
com.comphenix.protocol.injector.PacketFilterManager@1cdc5db3[
plugin=ProtocolLib v5.0.0-SNAPSHOT-636
server=CraftServer{serverName=Purpur,serverVersion=git-Purpur-1171,minecraftVersion=1.16.5}
reporter=com.comphenix.protocol.ProtocolLib$1@d58f19bf
minecraftVersion=(MC: 1.16.5)
asyncFilterManager=com.comphenix.protocol.async.AsyncFilterManager@94ea6a68
pluginVerifier=com.comphenix.protocol.injector.PluginVerifier@4f67f2ec
inboundListeners=com.comphenix.protocol.injector.SortedPacketListenerList@beeb1cbd
outboundListeners=com.comphenix.protocol.injector.SortedPacketListenerList@61ae11b5
registeredListeners=[]
packetInjector=com.comphenix.protocol.injector.netty.manager.NetworkManagerPacketInjector@778f6a16
playerInjectionHandler=com.comphenix.protocol.injector.netty.manager.NetworkManagerPlayerInjector@f265eb85
networkManagerInjector=com.comphenix.protocol.injector.netty.manager.NetworkManagerInjector@f6b9fa82
debug=false
closed=false
injected=true
]
Sender:
com.comphenix.protocol.ProtocolLib@bd21d250[
statistics=
packetTask=-1
tickCounter=0
configExpectedMod=-1
updater=com.comphenix.protocol.updater.SpigotUpdater@e674050d
redirectHandler=com.comphenix.protocol.ProtocolLib$2@ab4baec0
commandProtocol=com.comphenix.protocol.CommandProtocol@f7ae009b
commandPacket=com.comphenix.protocol.CommandPacket@60d7f11c
commandFilter=com.comphenix.protocol.CommandFilter@e17373a0
packetLogging=com.comphenix.protocol.PacketLogging@27f08067
skipDisable=false
isEnabled=true
loader=org.bukkit.plugin.java.JavaPluginLoader@8dbb1cb2
server=CraftServer{serverName=Purpur,serverVersion=git-Purpur-1171,minecraftVersion=1.16.5}
file=plugins/ProtocolLib (3).jar
description=org.bukkit.plugin.PluginDescriptionFile@a56a03a0
dataFolder=plugins/ProtocolLib
classLoader=PluginClassLoader{plugin=ProtocolLib v5.0.0-SNAPSHOT-636, pluginEnabled=true, url=plugins/ProtocolLib (3).jar}
naggable=true
newConfig=YamlConfiguration[path='', root='YamlConfiguration']
configFile=plugins/ProtocolLib/config.yml
logger=com.destroystokyo.paper.utils.PaperPluginLogger@992857b1
]
Version:
ProtocolLib v5.0.0-SNAPSHOT-636
Java Version:
16.0.2
Server:
git-Purpur-1171 (MC: 1.16.5)

[19:33:34 INFO]: [ProtocolLib] Disabling ProtocolLib v5.0.0-SNAPSHOT-636

@dmulloy2 help-me please :(

Use ProtocolLib 4.8.0 for now. The problem should not occur there.

You can use Java 17 with -DPaper.IgnoreJavaVersion=true on your startup parameters and Protocollib 5.0.0 will work as expected

update java