3.5.4 fails to load on Paper 1.21.1 #97

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1. github-actions

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   Dart2112

   on Jul 24, 2026
2. Dart2112 commented on Jul 24, 2026

   

   Dart2112

   on Jul 24, 2026

   Member

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   I see you are also running java 21, is it possible for you to run java 25. I'm not sure how paper handles java versions newer than what it is compiled for. I simply match my java version to whatever the latest spigot/paper version is building against, as of MC 26.1 that is Java 25.
3. Raineex commented on Jul 25, 2026

   

   Raineex

   on Jul 25, 2026

   Author

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   I tried Java 25, same thing. Honestly I think it's Paper 1.21.1-133's bundled ASM being too old to handle Java 25 class files, the remapper just can't parse it...

   Error log

   Starting org.bukkit.craftbukkit.Main
   *** Warning, you've not updated in a while! ***
   *** Please download a new build as per instructions from https://papermc.io/downloads/paper ***
   WARNING: A restricted method in java.lang.System has been called
   WARNING: java.lang.System::load has been called by org.fusesource.jansi.internal.JansiLoader in an unnamed module (file:/C:/Users/Work/Desktop/ROOT_CLEAN/libraries/org/fusesource/jansi/jansi/2.4.0/jansi-2.4.0.jar)
   WARNING: Use --enable-native-access=ALL-UNNAMED to avoid a warning for callers in this module
   WARNING: Restricted methods will be blocked in a future release unless native access is enabled
   
   WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
   WARNING: sun.misc.Unsafe::objectFieldOffset has been called by io.netty.util.internal.PlatformDependent0$4 (file:/C:/Users/Work/Desktop/ROOT_CLEAN/libraries/io/netty/netty-common/4.1.97.Final/netty-common-4.1.97.Final.jar)
   WARNING: Please consider reporting this to the maintainers of class io.netty.util.internal.PlatformDependent0$4
   WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
   
   ---> [03:30:55 INFO]: [bootstrap] Running Java 25 (Java HotSpot(TM) 64-Bit Server VM 25.0.3+9-LTS-195; Oracle Corporation null) on Windows 11 10.0 (amd64)
   
   [03:30:55 INFO]: [bootstrap] Loading Paper 1.21.1-133-ver/1.21.1@3cb8529 (2025-03-28T16:14:36Z) for Minecraft 1.21.1
   [03:30:56 INFO]: [PluginInitializerManager] Initializing plugins...
   [03:30:56 INFO]: [PluginRemapper] Remapping plugin 'plugins\AFKPlus-3.5.4.jar'...
   [03:30:57 ERROR]: [PluginRemapper] Encountered exception remapping plugins
   java.util.concurrent.CompletionException: java.lang.RuntimeException: Failed to remap plugin jar 'plugins\AFKPlus-3.5.4.jar'
           at java.base/java.util.concurrent.CompletableFuture.wrapInCompletionException(CompletableFuture.java:323) ~[?:?]
           at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:359) ~[?:?]
           at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:364) ~[?:?]
           at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:670) ~[?:?]
           at java.base/java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:503) ~[?:?]
           at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
           at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
           at java.base/java.lang.Thread.run(Thread.java:1474) ~[?:?]
   Caused by: java.lang.RuntimeException: Failed to remap plugin jar 'plugins\AFKPlus-3.5.4.jar'
           at io.papermc.paper.pluginremap.PluginRemapper.lambda$remap$7(PluginRemapper.java:358) ~[paper-1.21.1.jar:1.21.1-133-3cb8529]
           at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:667) ~[?:?]
           ... 4 more
   Caused by: java.lang.RuntimeException: Failed to execute task net/lapismc/afkplus/AFKPlus
           at net.neoforged.art.internal.AsyncHelper.invokeAll(AsyncHelper.java:56) ~[AutoRenamingTool-2.0.3.jar:?]
           at net.neoforged.art.internal.AsyncHelper.consumeAll(AsyncHelper.java:36) ~[AutoRenamingTool-2.0.3.jar:?]
           at net.neoforged.art.internal.RenamerImpl.run(RenamerImpl.java:177) ~[paper-1.21.1.jar:?]
           at net.neoforged.art.internal.RenamerImpl.run(RenamerImpl.java:95) ~[paper-1.21.1.jar:?]
           at io.papermc.paper.pluginremap.PluginRemapper.lambda$remap$7(PluginRemapper.java:355) ~[paper-1.21.1.jar:1.21.1-133-3cb8529]
           at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:667) ~[?:?]
           ... 4 more
   Caused by: java.util.concurrent.ExecutionException: java.lang.IllegalArgumentException: Unsupported class file major version 69
           at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:124) ~[?:?]
           at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:193) ~[?:?]
           at net.neoforged.art.internal.AsyncHelper.invokeAll(AsyncHelper.java:52) ~[AutoRenamingTool-2.0.3.jar:?]
           at net.neoforged.art.internal.AsyncHelper.consumeAll(AsyncHelper.java:36) ~[AutoRenamingTool-2.0.3.jar:?]
           at net.neoforged.art.internal.RenamerImpl.run(RenamerImpl.java:177) ~[paper-1.21.1.jar:?]
           at net.neoforged.art.internal.RenamerImpl.run(RenamerImpl.java:95) ~[paper-1.21.1.jar:?]
           at io.papermc.paper.pluginremap.PluginRemapper.lambda$remap$7(PluginRemapper.java:355) ~[paper-1.21.1.jar:1.21.1-133-3cb8529]
           at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:667) ~[?:?]
           ... 4 more
   Caused by: java.lang.IllegalArgumentException: Unsupported class file major version 69
           at org.objectweb.asm.ClassReader.<init>(ClassReader.java:200) ~[asm-9.7.1.jar:9.7.1]
           at org.objectweb.asm.ClassReader.<init>(ClassReader.java:180) ~[asm-9.7.1.jar:9.7.1]
           at org.objectweb.asm.ClassReader.<init>(ClassReader.java:166) ~[asm-9.7.1.jar:9.7.1]
           at net.neoforged.art.internal.ClassProviderImpl$ClassInfo.<init>(ClassProviderImpl.java:104) ~[AutoRenamingTool-2.0.3.jar:?]
           at net.neoforged.art.internal.ClassProviderBuilderImpl.lambda$addClass$1(ClassProviderBuilderImpl.java:64) ~[AutoRenamingTool-2.0.3.jar:?]
           at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1724) ~[?:?]
           at net.neoforged.art.internal.ClassProviderBuilderImpl.addClass(ClassProviderBuilderImpl.java:64) ~[AutoRenamingTool-2.0.3.jar:?]
           at net.neoforged.art.internal.RenamerImpl.lambda$run$2(RenamerImpl.java:178) ~[paper-1.21.1.jar:?]
           at net.neoforged.art.internal.AsyncHelper.lambda$null$0(AsyncHelper.java:33) ~[AutoRenamingTool-2.0.3.jar:?]
           at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:328) ~[?:?]
           ... 3 more