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Error getting implementation for class dev.lone.cosmeticscore.nms.packet.Packets - NMS null #359

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Error getting implementation for class dev.lone.cosmeticscore.nms.packet.Packets - NMS null#359
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type: bugSomething isn't working

Description

@WieszczY85
WieszczY85
opened on Sep 1, 2026

Terms

  • I'm using the very latest version of CosmeticsCore and its dependencies.
  • I already searched on this Github page to check if the same issue was already reported.
  • I already searched on the plugin wiki to know if a solution is already known.
  • I already searched on the Discord server to know if anyone already provided a solution in the past for the issue.

Discord tag (optional)

WieszczY

What happened?

The plugin doesn't start at all and constantly restarts the server. I have the following logs in the console.

Steps to reproduce the issue

  1. I put the plugin in the server's plugins folder.
  2. I start the server.
  3. The server restarts for no reason.

Server version

This server is running Paper version 26.2-121-main@a2a42c5 (2026-08-29T11:32:25Z) (Implementing API version 26.2.build.121-stable)

CosmeticsCore Version

CosmeticsCore 1.3.12

ProtocolLib Version

ProtocolLib version 5.5.0-SNAPSHOT-f0e959a

FULL server log

No response

Error (optional)

[16:05:59 INFO]: [CosmeticsCore] Enabling CosmeticsCore v1.3.12
[16:05:59 INFO]: [CosmeticsCore] Loading library FastNbt-jar (remapped)...
[16:06:00 INFO]: [CosmeticsCore] Downloaded library https://maven-central.storage-download.googleapis.com/maven2/beer/devs/FastNbt-jar/1.4.18/FastNbt-jar-1.4.18.jar
[16:06:00 INFO]: [CosmeticsCore] Downloaded library https://repo.alessiodp.com/releases/com/alessiodp/libby/maven/resolver/libby-maven-resolver/1.0.1/libby-maven-resolver-1.0.1.jar
[16:06:01 INFO]: [CosmeticsCore] Loading library commons-math3...
[16:06:01 INFO]: [CosmeticsCore] Downloaded library https://maven-central.storage-download.googleapis.com/maven2/org/apache/commons/commons-math3/3.6.1/commons-math3-3.6.1.jar
[16:06:04 INFO]: [CosmeticsCore] Loading library jansi...
[16:06:05 INFO]: [CosmeticsCore] Downloaded library https://maven-central.storage-download.googleapis.com/maven2/org/fusesource/jansi/jansi/2.4.2/jansi-2.4.2.jar
[16:06:05 INFO]: [CosmeticsCore] Loading library adventure-api...
[16:06:06 INFO]: [CosmeticsCore] Downloaded library https://maven-central.storage-download.googleapis.com/maven2/net/kyori/adventure-api/4.23.0/adventure-api-4.23.0.jar
[16:06:09 INFO]: [CosmeticsCore] Loading library adventure-key
[16:06:09 INFO]: [CosmeticsCore] Loading library examination-api
[16:06:09 INFO]: [CosmeticsCore] Loading library examination-string
[16:06:09 INFO]: [CosmeticsCore] Loading library annotations
[16:06:09 INFO]: [CosmeticsCore] Loading library adventure-text-minimessage...
[16:06:10 INFO]: [CosmeticsCore] Downloaded library https://maven-central.storage-download.googleapis.com/maven2/net/kyori/adventure-text-minimessage/4.23.0/adventure-text-minimessage-4.23.0.jar
[16:06:12 INFO]: [CosmeticsCore] Loading library adventure-api
[16:06:12 INFO]: [CosmeticsCore] Loading library adventure-key
[16:06:12 INFO]: [CosmeticsCore] Loading library examination-api
[16:06:12 INFO]: [CosmeticsCore] Loading library examination-string
[16:06:12 INFO]: [CosmeticsCore] Loading library annotations
[16:06:12 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-gson...
[16:06:12 INFO]: [CosmeticsCore] Downloaded library https://maven-central.storage-download.googleapis.com/maven2/net/kyori/adventure-text-serializer-gson/4.23.0/adventure-text-serializer-gson-4.23.0.jar
[16:06:20 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-json
[16:06:20 INFO]: [CosmeticsCore] Loading library adventure-api
[16:06:20 INFO]: [CosmeticsCore] Loading library adventure-key
[16:06:20 INFO]: [CosmeticsCore] Loading library examination-api
[16:06:20 INFO]: [CosmeticsCore] Loading library examination-string
[16:06:20 INFO]: [CosmeticsCore] Loading library option
[16:06:20 INFO]: [CosmeticsCore] Loading library jspecify
[16:06:20 INFO]: [CosmeticsCore] Loading library gson
[16:06:20 INFO]: [CosmeticsCore] Loading library auto-service-annotations
[16:06:20 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-commons
[16:06:20 INFO]: [CosmeticsCore] Loading library annotations
[16:06:20 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-gson-legacy-impl...
[16:06:20 INFO]: [CosmeticsCore] Downloaded library https://maven-central.storage-download.googleapis.com/maven2/net/kyori/adventure-text-serializer-gson-legacy-impl/4.23.0/adventure-text-serializer-gson-legacy-impl-4.23.0.jar
[16:06:27 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-gson
[16:06:27 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-json
[16:06:27 INFO]: [CosmeticsCore] Loading library option
[16:06:27 INFO]: [CosmeticsCore] Loading library jspecify
[16:06:27 INFO]: [CosmeticsCore] Loading library gson
[16:06:27 INFO]: [CosmeticsCore] Loading library auto-service-annotations
[16:06:27 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-commons
[16:06:27 INFO]: [CosmeticsCore] Loading library annotations
[16:06:27 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-json-legacy-impl
[16:06:27 INFO]: [CosmeticsCore] Loading library adventure-api
[16:06:27 INFO]: [CosmeticsCore] Loading library adventure-key
[16:06:27 INFO]: [CosmeticsCore] Loading library examination-api
[16:06:27 INFO]: [CosmeticsCore] Loading library examination-string
[16:06:27 INFO]: [CosmeticsCore] Loading library adventure-nbt
[16:06:27 INFO]: [CosmeticsCore] Loading library adventure-platform-bukkit...
[16:06:27 INFO]: [CosmeticsCore] Downloaded library https://maven-central.storage-download.googleapis.com/maven2/net/kyori/adventure-platform-bukkit/4.4.0/adventure-platform-bukkit-4.4.0.jar
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-platform-api
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-api
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-key
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-bungeecord
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-legacy
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-nbt
[16:06:34 INFO]: [CosmeticsCore] Loading library examination-api
[16:06:34 INFO]: [CosmeticsCore] Loading library examination-string
[16:06:34 INFO]: [CosmeticsCore] Loading library annotations
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-gson
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-json
[16:06:34 INFO]: [CosmeticsCore] Loading library option
[16:06:34 INFO]: [CosmeticsCore] Loading library jspecify
[16:06:34 INFO]: [CosmeticsCore] Loading library auto-service-annotations
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-commons
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-gson-legacy-impl
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-text-serializer-json-legacy-impl
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-platform-facet
[16:06:34 INFO]: [CosmeticsCore] Loading library adventure-platform-viaversion
[16:06:34 ERROR]: [CosmeticsCore] Error getting implementation for class dev.lone.cosmeticscore.nms.packet.Packets - NMS null
[16:06:34 WARN]: java.lang.ClassNotFoundException: dev.lone.cosmeticscore.nms.packet.impl.null
[16:06:34 WARN]: 	at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:208)
[16:06:34 WARN]: 	at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:175)
[16:06:34 WARN]: 	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:490)
[16:06:34 WARN]: 	at java.base/java.lang.Class.forName0(Native Method)
[16:06:34 WARN]: 	at java.base/java.lang.Class.forName(Class.java:467)
[16:06:34 WARN]: 	at java.base/java.lang.Class.forName(Class.java:458)
[16:06:34 WARN]: 	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.Nms.findImplementation(SourceFile:96)
[16:06:34 WARN]: 	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.packet.Packets.<init>(SourceFile:35)
[16:06:34 WARN]: 	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.packet.Packets.cj(SourceFile:50)
[16:06:34 WARN]: 	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.Nms.cj(SourceFile:39)
[16:06:34 WARN]: 	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.Main.onEnable(SourceFile:81)
[16:06:34 WARN]: 	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:279)
[16:06:34 WARN]: 	at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:201)
[16:06:34 WARN]: 	at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:109)
[16:06:34 WARN]: 	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:519)
[16:06:34 WARN]: 	at org.bukkit.craftbukkit.CraftServer.enablePlugin(CraftServer.java:633)
[16:06:34 WARN]: 	at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:590)
[16:06:34 WARN]: 	at net.minecraft.server.MinecraftServer.initPostWorld(MinecraftServer.java:648)
[16:06:34 WARN]: 	at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:343)
[16:06:34 WARN]: 	at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1266)
[16:06:34 WARN]: 	at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:303)
[16:06:34 WARN]: 	at java.base/java.lang.Thread.run(Thread.java:1474)
[16:06:34 INFO]: [CosmeticsCore] Disabling CosmeticsCore v1.3.12
[16:06:34 ERROR]: Error occurred while disabling CosmeticsCore v1.3.12
java.lang.NullPointerException: Cannot read field "lo" because "dev.lone.cosmeticscore.nms.packet.Packets.lp" is null
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.packet.Packets.da(SourceFile:40) ~[?:?]
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.Main.onDisable(SourceFile:131) ~[?:?]
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:285) ~[paper-api-26.2.build.121-stable.jar:?]
	at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.disablePlugin(PaperPluginInstanceManager.java:236) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.disablePlugin(PaperPluginManagerImpl.java:114) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:549) ~[paper-api-26.2.build.121-stable.jar:?]
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.Nms.findImplementation(SourceFile:115) ~[?:?]
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.packet.Packets.<init>(SourceFile:35) ~[?:?]
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.packet.Packets.cj(SourceFile:50) ~[?:?]
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.Nms.cj(SourceFile:39) ~[?:?]
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.Main.onEnable(SourceFile:81) ~[?:?]
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:279) ~[paper-api-26.2.build.121-stable.jar:?]
	at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:201) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:109) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:519) ~[paper-api-26.2.build.121-stable.jar:?]
	at org.bukkit.craftbukkit.CraftServer.enablePlugin(CraftServer.java:633) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:590) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at net.minecraft.server.MinecraftServer.initPostWorld(MinecraftServer.java:648) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:343) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1266) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:303) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at java.base/java.lang.Thread.run(Thread.java:1474) ~[?:?]
[16:06:34 ERROR]: Error occurred while enabling CosmeticsCore v1.3.12 (Is it up to date?)
java.lang.IllegalStateException: The plugin classloader for CosmeticsCore has thrown a zip file error.
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:228) ~[paper-api-26.2.build.121-stable.jar:?]
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:557) ~[?:?]
	at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:180) ~[paper-api-26.2.build.121-stable.jar:?]
	at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:175) ~[paper-api-26.2.build.121-stable.jar:?]
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:490) ~[?:?]
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.nms.Nms.cj(SourceFile:40) ~[?:?]
	at CosmeticsCore_1.3.12.jar//dev.lone.cosmeticscore.Main.onEnable(SourceFile:81) ~[?:?]
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:279) ~[paper-api-26.2.build.121-stable.jar:?]
	at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:201) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:109) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:519) ~[paper-api-26.2.build.121-stable.jar:?]
	at org.bukkit.craftbukkit.CraftServer.enablePlugin(CraftServer.java:633) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:590) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at net.minecraft.server.MinecraftServer.initPostWorld(MinecraftServer.java:648) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:343) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1266) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:303) ~[paper-26.2.jar:26.2-121-a2a42c5]
	at java.base/java.lang.Thread.run(Thread.java:1474) ~[?:?]
Caused by: java.lang.IllegalStateException: zip file closed
	at java.base/java.util.zip.ZipFile.ensureOpen(ZipFile.java:826) ~[?:?]
	at java.base/java.util.zip.ZipFile.getMetaInfVersions(ZipFile.java:1073) ~[?:?]
	at java.base/java.util.zip.ZipFile$1.getMetaInfVersions(ZipFile.java:1116) ~[?:?]
	at java.base/java.util.jar.JarFile.getVersionedEntry(JarFile.java:590) ~[?:?]
	at java.base/java.util.jar.JarFile.getEntry(JarFile.java:499) ~[?:?]
	at java.base/java.util.jar.JarFile.getJarEntry(JarFile.java:460) ~[?:?]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:223) ~[paper-api-26.2.build.121-stable.jar:?]
	... 17 more

CosmeticsCore config.yml

The config file didn't even have time to generate.

Problematic items yml configuration file (optional)



Other files, you can drag and drop them here to upload. (optional)


No response


Screenshots/Videos (you can drag and drop files or paste links)


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