java.lang.NoClassDefFoundError: org/yaml/snakeyaml/external/biz/base64Coder/Base64Coder on plugin loads

[SpeastTV]

Checklist

• I have searched the existing issues and the documentation
• I ticked all the boxes without actually reading them
• I am using latest Leaf build from https://www.leafmc.one/download
• I tested and couldn't replicate this issue on latest Paper or Purpur build

What behaviour is observed?

The plugin AxAuctions does load without an error on paper, but when starting the server with Leaf and the Plugin this error comes in the console and the plugin disables itself.
I think it has something to do with the snakeyaml version. Paper still uses "org.yaml:snakeyaml:2.2", but Leaf upgraded independent of Paper to "org.yaml:snakeyaml:2.5", which is not supported by the plugin because it targets paper.

[23:37:18 INFO]: [AxAuctions] Enabling AxAuctions v1.31.0
[23:37:18 INFO]: ╠ Downloading en_us language files.. (version: 1.21.8)
[23:37:19 ERROR]: Error occurred while enabling AxAuctions v1.31.0 (Is it up to date?)
java.lang.NoClassDefFoundError: org/yaml/snakeyaml/external/biz/base64Coder/Base64Coder
        at AxAuctions-1.31.0.jar//com.artillexstudios.axauctions.lang.LanguageManager.reload(LanguageManager.java:53) ~[?:?]
        at AxAuctions-1.31.0.jar//com.artillexstudios.axauctions.AxAuctions.enable(AxAuctions.java:123) ~[?:?]
        at AxAuctions-1.31.0.jar//com.artillexstudios.axauctions.libs.axapi.AxPlugin.onEnable(AxPlugin.java:146) ~[?:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:280) ~[leaf-api-1.21.8-R0.1-SNAPSHOT.jar:?]
        at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:202) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:109) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:519) ~[leaf-api-1.21.8-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.craftbukkit.CraftServer.enablePlugin(CraftServer.java:671) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:627) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.loadWorld0(MinecraftServer.java:743) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.loadLevel(MinecraftServer.java:488) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:332) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1185) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:298) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
Caused by: java.lang.ClassNotFoundException: org.yaml.snakeyaml.external.biz.base64Coder.Base64Coder
        at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:205) ~[leaf-api-1.21.8-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:172) ~[leaf-api-1.21.8-R0.1-SNAPSHOT.jar:?]
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526) ~[?:?]
        ... 15 more
[23:37:19 INFO]: [AxAuctions] Disabling AxAuctions v1.31.0
[23:37:19 ERROR]: Error occurred while disabling AxAuctions v1.31.0
java.lang.NullPointerException: Cannot invoke "com.artillexstudios.axauctions.database.Database.disable()" because "com.artillexstudios.axauctions.AxAuctions.database" is null
        at AxAuctions-1.31.0.jar//com.artillexstudios.axauctions.AxAuctions.disable(AxAuctions.java:194) ~[?:?]
        at AxAuctions-1.31.0.jar//com.artillexstudios.axauctions.libs.axapi.AxPlugin.onDisable(AxPlugin.java:172) ~[?:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:286) ~[leaf-api-1.21.8-R0.1-SNAPSHOT.jar:?]
        at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.disablePlugin(PaperPluginInstanceManager.java:237) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.disablePlugin(PaperPluginManagerImpl.java:114) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:549) ~[leaf-api-1.21.8-R0.1-SNAPSHOT.jar:?]
        at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:206) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:109) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:519) ~[leaf-api-1.21.8-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.craftbukkit.CraftServer.enablePlugin(CraftServer.java:671) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:627) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.loadWorld0(MinecraftServer.java:743) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.loadLevel(MinecraftServer.java:488) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:332) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1185) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:298) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]

What is the expected behavior?

The plugin loads without an error normaly.

How to reproduce?

1. Put AxAuctions Plugin in the Plugin folder.
2. Start the Server.
3. See the error in the console and that it is red in /pl.

Spark profiler link

https://spark.lucko.me/fld4BUuKF7

Error log (if applicable)

https://mclo.gs/JdCcYd0

[Dreeam-qwq]

Hi, it's because there is a plugin that is using deprecated library methods from SnakeYAML.

SnakeYAML removed the Base64Coder class since version 2.3, see snakeyaml#3f0beda.
So, it's not recommended to continue relying on it.

As the best practice, it's better to use the built-in Base64 utility methods provided by Java (java.util.Base64)
Please check the stacktrace to identify which plugin is using Base64Coder and report it to the plugin's support team to let them migrate the implementation.

For most cases, if the plugin just simply uses:

• Base64Coder#encodeLines
• Base64Coder#decodeLines

to encode/decode ItemStack data or other serialized objects.
These can be directly replaced with:

• Base64.getEncoder().encodeToString
• Base64.getMimeDecoder().decode

This approach is more standard, has better performance, and maintains the same behavior.

Notes for plugin developers:
If persistent Base64 data already exists on the user end, use Base64.getMimeDecoder().decode, to use the MIME type decoder to ensure compatibility with the old data, and use Base64.getEncoder() to encode them to the standard type. If there is no existing data, then it's safe to use the standard Base64 decoder (Base64.getDecoder()) for the data decoding.

Here is a reference PR for the migration:
Athlaeos/ValhallaTrinkets#5

It's also better to create test cases to ensure that no inconsistent edge cases exist after the migration.

---

This Base64Coder class was added back in the latest Leaf 1.21.11 for compatibility, and for server owners, you can add -DLeaf.enable-base64coder-warning flag to catch these plugins during the server runtime, and report to the corresponding plugin support team.

[SpeastTV]

Hi, you should report it to AxAuctions, they need to use java.util.Base64 instead of snakeyaml's Base64Coder to encode or decode. Since this util class is deprecated in the newer version of snakeyaml, it's not proper to continue relying on it.

Here is a migration example: snakeyaml/snakeyaml@3f0beda

Thank you, will try.

[TheArmagan]

I'm having same issue with ValhallaMMO too.

[14:27:03 WARN]: [ValhallaMMO] Task #99 for ValhallaMMO vpremium_1.10.1 generated an exception
java.lang.NoClassDefFoundError: org/yaml/snakeyaml/external/biz/base64Coder/Base64Coder
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.ItemSerializer.itemStackFromBase64(ItemSerializer.java:32) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.Utils.deserializeItemStack(Utils.java:210) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.TrinketsManager.getTrinketInventory(TrinketsManager.java:72) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.TrinketCache.getOrCache(TrinketCache.java:18) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.valhallammo.TrinketVanillaAttributeSource.fetch(TrinketVanillaAttributeSource.java:27) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.playerstats.AccumulativeStatManager.getStats(AccumulativeStatManager.java:426) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.playerstats.AccumulativeStatManager.getCachedStats(AccumulativeStatManager.java:476) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.entities.EntityAttributeStats.updateSingleStat(EntityAttributeStats.java:79) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.entities.EntityAttributeStats.updateStats(EntityAttributeStats.java:71) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.listeners.MovementListener.lambda$new$0(MovementListener.java:44) ~[?:?]
        at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:78) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:474) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1709) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1566) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1284) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:298) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
Caused by: java.lang.ClassNotFoundException: org.yaml.snakeyaml.external.biz.base64Coder.Base64Coder
        ... 17 more

[YuanYuanOwO]

I'm having same issue with ValhallaMMO too.

[14:27:03 WARN]: [ValhallaMMO] Task #99 for ValhallaMMO vpremium_1.10.1 generated an exception
java.lang.NoClassDefFoundError: org/yaml/snakeyaml/external/biz/base64Coder/Base64Coder
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.ItemSerializer.itemStackFromBase64(ItemSerializer.java:32) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.Utils.deserializeItemStack(Utils.java:210) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.TrinketsManager.getTrinketInventory(TrinketsManager.java:72) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.TrinketCache.getOrCache(TrinketCache.java:18) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.valhallammo.TrinketVanillaAttributeSource.fetch(TrinketVanillaAttributeSource.java:27) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.playerstats.AccumulativeStatManager.getStats(AccumulativeStatManager.java:426) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.playerstats.AccumulativeStatManager.getCachedStats(AccumulativeStatManager.java:476) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.entities.EntityAttributeStats.updateSingleStat(EntityAttributeStats.java:79) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.entities.EntityAttributeStats.updateStats(EntityAttributeStats.java:71) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.listeners.MovementListener.lambda$new$0(MovementListener.java:44) ~[?:?]
        at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:78) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:474) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1709) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1566) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1284) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:298) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
Caused by: java.lang.ClassNotFoundException: org.yaml.snakeyaml.external.biz.base64Coder.Base64Coder
        ... 17 more

contact ValhallaMMO support
or waiting for ValhallaMMO new release

[Dreeam-qwq]

I'm having same issue with ValhallaMMO too.

[14:27:03 WARN]: [ValhallaMMO] Task #99 for ValhallaMMO vpremium_1.10.1 generated an exception
java.lang.NoClassDefFoundError: org/yaml/snakeyaml/external/biz/base64Coder/Base64Coder
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.ItemSerializer.itemStackFromBase64(ItemSerializer.java:32) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.Utils.deserializeItemStack(Utils.java:210) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.TrinketsManager.getTrinketInventory(TrinketsManager.java:72) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.TrinketCache.getOrCache(TrinketCache.java:18) ~[?:?]
        at ValhallaTrinkets_2.5.jar//me.athlaeos.valhallatrinkets.valhallammo.TrinketVanillaAttributeSource.fetch(TrinketVanillaAttributeSource.java:27) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.playerstats.AccumulativeStatManager.getStats(AccumulativeStatManager.java:426) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.playerstats.AccumulativeStatManager.getCachedStats(AccumulativeStatManager.java:476) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.entities.EntityAttributeStats.updateSingleStat(EntityAttributeStats.java:79) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.entities.EntityAttributeStats.updateStats(EntityAttributeStats.java:71) ~[?:?]
        at ValhallaMMO_premium_1.10.1.jar//me.athlaeos.valhallammo.listeners.MovementListener.lambda$new$0(MovementListener.java:44) ~[?:?]
        at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:78) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:474) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1709) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1566) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1284) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:298) ~[leaf-1.21.8.jar:1.21.8-160-c706428]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
Caused by: java.lang.ClassNotFoundException: org.yaml.snakeyaml.external.biz.base64Coder.Base64Coder
        ... 17 more

Will be fixed in Athlaeos/ValhallaTrinkets#5
Waiting for their devs to merge