Trouble setting up a 1.12.2 MDK in 2026

Hello,

I’m having trouble setting up the development environment in IntelliJ IDEA using the Minecraft Forge MDK version net.minecraftforge:forge:1.12.2-14.23.5.2864. I’m using Java 8.

I haven’t modified anything — I simply downloaded the MDK ZIP from the official Forge website, extracted it, and ran the Gradle setup commands. Minecraft launches for a few seconds and then crashes with some unusual errors:

Caused by: java.lang.IllegalArgumentException

Caused by: java.lang.NullPointerException

[Client thread/ERROR] [FML]: There was a problem reading the entry module-info.class in the jar C:\Users\tmh.gradle\caches\modules-2\files-2.1\org.ow2.asm\asm\6.2\1b6c4ff09ce03f3052429139c2a68e295cae6604\asm-6.2.jar - probably a corrupt zip net.minecraftforge.fml.common.LoaderException: java.lang.IllegalArgumentException

at net.minecraftforge.fml.common.discovery.asm.ASMModParser.<init>(ASMModParser.java:63) ~[ASMModParser.class:?]

For some reason, it appears to be attempting to load several Gradle .jar files as Minecraft mods, and it does this with quite a large number of jars.

I haven’t changed the build.gradle file at all — everything is still using the default configuration — so I’m not sure why it’s trying to load them as mods.