Encountering NullPointerException despite setting ProtocolLib up as explained in the README.

[Andre601]

I'm currently struggling to properly hook into ProtocolLib to use for manipulating the Server list's MOTD and alike.

Whenever my plugin starts am I encountering this particular error:

[18:27:05 ERROR]: Could not pass event ServerLoadEvent to AdvancedServerList v1.0.0
java.lang.NullPointerException: Cannot invoke "com.comphenix.protocol.ProtocolManager.addPacketListener(com.comphenix.protocol.events.PacketListener)" because "this.protocolManager" is null
        at ch.andre601.advancedserverlist.spigot.events.PingEvent.loadPacketListener(PingEvent.java:29) ~[AdvancedServerList-Spigot-1.0.0.jar:?]
        at ch.andre601.advancedserverlist.spigot.events.PingEvent.<init>(PingEvent.java:25) ~[AdvancedServerList-Spigot-1.0.0.jar:?]
        at ch.andre601.advancedserverlist.spigot.events.LoadEvent.onServerLoad(LoadEvent.java:32) ~[AdvancedServerList-Spigot-1.0.0.jar:?]
        at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor10.execute(Unknown Source) ~[?:?]
        at org.bukkit.plugin.EventExecutor.lambda$create$1(EventExecutor.java:75) ~[paper-api-1.19-R0.1-SNAPSHOT.jar:?]
        at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:80) ~[paper-api-1.19-R0.1-SNAPSHOT.jar:git-Paper-12]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[paper-api-1.19-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:664) ~[paper-api-1.19-R0.1-SNAPSHOT.jar:?]
        at net.minecraft.server.MinecraftServer.loadWorld0(MinecraftServer.java:634) ~[paper-1.19.jar:git-Paper-12]
        at net.minecraft.server.MinecraftServer.loadLevel(MinecraftServer.java:419) ~[paper-1.19.jar:git-Paper-12]
        at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:306) ~[paper-1.19.jar:git-Paper-12]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1121) ~[paper-1.19.jar:git-Paper-12]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:302) ~[paper-1.19.jar:git-Paper-12]
        at java.lang.Thread.run(Thread.java:833) ~[?:?]

I first thought this might be because I load events on the ServerLoadEvent and also call ProtocolLibrary.getProtocolManager() in the constructor.

Here's the old code I used for reference:

    @EventHandler
    public void onServerLoad(ServerLoadEvent event){
        if(!plugin.getServer().getPluginManager().isPluginEnabled("ProtocolLib")){
            plugin.getCore().getPluginLogger().warn("ProtocolLib not found! AdvancedServerList requires it to work on Spigot!");
            
            plugin.getServer().getPluginManager().disablePlugin(plugin);
            return;
        }
    
        PluginManager manager = plugin.getServer().getPluginManager();
        manager.registerEvents(new JoinEvent(plugin), plugin);
        manager.registerEvents(new PingEvent(plugin, ProtocolLibrary.getProtocolManager()), plugin);
    }

But even when I create the ProtocolManager instance during the onEnable() of my plugin and pass that on to the LoadEvent class through the constructor is the same error appearing.

The reason why I'm doing this weird setup with the ServerLoadEvent and not just do stuff during the onEnable() of my plugin is a particular issue where a plugin may load after any defined (soft)depend, causing checks such as isPluginEnabled to return false because the plugin hasn't been enabled yet.

Here is the full class for the Packet handling:
https://github.com/Andre601/AdvancedServerList/blob/master/spigot/src/main/java/ch/andre601/advancedserverlist/spigot/events/PingEvent.java

I appreciate any help that can be given here.

[Andre601]

One guess I have is that I'm using 4.8.0 of ProtocolLib for the API while v5 is used on the server (At least I recall it being the v5 dev build since it is a 1.19 server).

If there really is a difference, is there an easy way to support both versions in some way? Not really want to make yet another module just to include two ProtocolLib versions.

[derklaro]

Try to set the scope of the ProtocolLib dependency to provided.

[Andre601]

This actually worked, thank you.