MCA Selector Missing JavaFX: How to Fix the Launch Error

ByAdmin

You double-click the MCA Selector .jar and, instead of the map view, a dialog complains that JavaFX is missing — variants of the message include “Fails to find JavaFX” and errors naming javafx/scene/paint/Color. This is tracked upstream in issues #379 and #518, and it has nothing to do with your world: it is purely about the Java runtime you launched the .jar with.

Why it happens

MCA Selector’s interface is built with JavaFX, but JavaFX is not part of a standard Java installation. The current release needs a 64-bit JRE 21 or newer that includes JavaFX — either pre-packed or installed separately, as the official installation guide puts it. Most people’s Java (the one bundled with Minecraft, or a plain OpenJDK download) does not include JavaFX, so the .jar starts, cannot find the toolkit, and stops. The full background is in our guide to MCA Selector’s Java requirements.

Fix 1: use a Java runtime with JavaFX built in (easiest)

  1. Download a JRE 21 (or newer) with JavaFX pre-packed — the official guide’s example is Azul Zulu JRE-FX 21. Make sure you pick the 64-bit FX edition, not the plain JRE.
  2. Install it, and make sure it is the Java your system uses for .jar files (on Windows, right-click the .jar → Open with → choose the new runtime; or launch from a terminal as in Fix 2).
  3. Start MCA Selector again. The JavaFX dialog should be gone.

Fix 2: add the JavaFX SDK yourself

If you prefer to keep your existing Java 21+ runtime, download the JavaFX SDK separately and tell Java where it is when launching, exactly as the official installation guide describes:

java --module-path <path-to-javafx>/lib --add-modules ALL-MODULE-PATH -jar mcaselector-2.9.jar

  • Replace <path-to-javafx> with the folder you extracted the JavaFX SDK into.
  • On Linux, your distribution’s openjfx package provides the same modules — install it via your package manager, or use the native packages in our Linux install guide.

Or skip Java entirely on Windows

Since version 2.8, the Windows installer (mcaselector-2.9-setup.exe) pre-packages its own runtime, so .exe users do not need to install Java or JavaFX at all. If the .jar route keeps fighting you on Windows, switching to the installer from the download page is the simplest permanent fix.

If it still does not work

Issues #379 and #518 are still open upstream, but almost every case resolves to the runtime: run java -version in a terminal and confirm it reports 21 or newer and is the same Java that launches the .jar — having Java 21 installed does not help if the .jar is still associated with an older runtime. If the version and the JavaFX modules are both right and it still fails, report it on the issue with your exact error text and launch command.

Get the Current Version First

Several of the problems in this guide disappear on the current release. MCA Selector 2.9 is free and open source — get the Windows installer, the cross-platform .jar, the macOS .dmg or the Linux .deb/.rpm from the MCA Selector download page, where every button points at the official GitHub release files with their SHA-256 checksums.

More troubleshooting

This page is part of our MCA Selector troubleshooting hub, which groups every known launch, loading and editing problem by symptom.

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