Error Codes › A fatal error has been detected by the Java Runtime Environment

A fatal error has been detected by the Java Runtime Environment

COAL-012 · JVM native crash

The JVM itself crashed rather than throwing an exception - SIGSEGV or EXCEPTION_ACCESS_VIOLATION. What the hs_err_pid file tells you, and what to do next.

What it looks like in the log

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007f9c8a1b2c40, pid=3412, tid=3419
#
# An error report file with more information is saved as:
# /home/mc/server/hs_err_pid3412.log

What it means

This is a level below a normal Minecraft crash: the Java process died at the native level, so there is no Java stack trace and no crash report. On Windows the same thing appears as EXCEPTION_ACCESS_VIOLATION. The causes are native code (a mod shipping its own compiled library), a faulty JVM install, or failing hardware.

How to fix it

Open the hs_err_pid*.log the message points to. The "Problematic frame" line near the top names the library that crashed - if it is a .dll or .so belonging to a mod, that is your answer.
Update or reinstall Java. Use a current LTS build (Temurin 17 or 21, matching your Minecraft version). A half-installed or very old JVM causes this more often than people expect.
Remove recently added mods one at a time, starting with anything that does hardware-adjacent work.
If the crash moves around at random, test your RAM with MemTest86. A native crash with no consistent frame is a classic bad-memory symptom, especially on a machine that also misbehaves outside Minecraft.