PerlandFailure catalogue

The mod loader's installer needs a newer Java than the server has

Fatalinstaller_java_mismatch

The loader's installer, run at startup on the server's Java, refused to run because that Java is too old, so the loader was not installed.

What the log shows

Written example3 lines
[mc-image-helper] 10:44:18.061 INFO  : Installing Quilt version 1.16.5 with loader 0.29.2
Quilt Installer requires Java 17 or greater to run.
[mc-image-helper] 10:44:18.733 ERROR : 'install-quilt' command failed. Version is 1.51.4-java8

Your log will have other names, versions and times. Search a line of it from all failures.

What it means

A modded server installs its mod loader at startup by running the loader’s official installer. The installer runs on the same Java as the server will. Here the installer checked that Java, found it too old, and stopped before installing anything, so the server could not start.

The diagnosis reads the installer’s own sentence, which names the Java it needs. The startup helper’s error lines that follow are the same failure and are not shown as separate issues.

Why it happens

  • An old Minecraft version picks an old Java. Server images for Minecraft up to 1.16.5 usually run Java 8, but the Quilt installer needs Java 17 or newer, even for those old versions.
  • The Java version was set by hand to one older than the installer needs.

How to fix

  1. Choose a Java version at least as new as the one the message names (17 for the Quilt installer).
  2. Docker (itzg image): pick an image tag with that Java, such as itzg/minecraft-server:java17.
  3. Start the server again. Old Minecraft versions such as Quilt for 1.14.4 to 1.16.5 start on Java 17.

In Perland

The issue appears in the server’s Diagnosis tab, and its fix leads to the Java version in Settings. Perland now gives Quilt servers Java 17 or newer by itself; servers created before that may still run Java 8 until you choose a newer Java there.

References

Details the diagnosis reports

Perland's server diagnosis returns this failure as the code installer_java_mismatch with these parameters, each present only when the log names it.

ParameterMeaning
installerThe installer that refused to run, in lower case, such as quilt.
requiredJavaThe lowest Java version the installer says it needs, such as 17.

Log lines this page covers

  • Quilt Installer requires Java 17 or greater to run.