DEPTANA
RUEN

Crash Diagnostics: UnsupportedClassVersionError

Java 8 / Java 17 / Java 21

Pre-loaded example showing how bytecode versions map to required Java runtimes.

Java Version Mismatch (requires Java 21)

Compiled for Java 21 (bytecode 65.0), running on 17.0.9.

Matched error signature in log:
Exception in thread "main" java.lang.UnsupportedClassVersionError: net/minecraft/bundler/Main has been compiled by a more recent version of the Java Runtime (class file version 65.0), this version of the Java Runtime only recognizes class file versions up to 61.0
Troubleshooting steps:
  1. Install Java 21 and select it in your launcher settings.

Questions & reference

How do I fix: Java Version Mismatch (requires Java 21)?

Compiled for Java 21 (bytecode 65.0), running on 17.0.9. Install Java 21 and select it in your launcher settings.

Where do I find my Minecraft error log?

Open your game profile folder. Copy a file from crash-reports or logs/latest.log. Exit Code 1 alone does not explain the crash.

Where is my log sent?

Analysis runs in your browser. Your log is not uploaded to DEPTANA, stored in settings, or included in a shared URL. The text limit is two million characters.

Does a match prove the cause?

Diagnostics checks known error signatures. A match suggests what to inspect; it does not prove the sole cause. If no rule matches, the tool says so.

Related calculators & presets in this section

Crash Log Analyzer (paste your log)Sodium & OptiFine Conflict (MixinApplyError)Missing Mod Dependencies (ModLoadingException)Ticking Entity World CrashOutOfMemoryError: Java heap spaceGLFW Error 65542 (OpenGL Driver)SocketException: Connection reset (getsockopt)Exit Code -1073740791 & EXCEPTION_ACCESS_VIOLATIONDuplicateModsFoundException (Duplicate Mods)Exception Ticking World CrashNightConfig ParsingException (Corrupted .toml)Corrupted level.dat (ReportedNbtException)