I have been using Java for a while now, but admittedly have been more into Python in recent years. Anyway, I am following a tutorial on Youtube to setup the IntelliJ IDE for making a Forge mod (the channel is "Modding by Kaupenjoe"). I have done everything in the first video to the letter, and yet when I run the "runClient" task via Gradle to see if I can boot up Minecraft with my tutorial mod (nothing new in the mod, just blank template basically), I receive the following error:
 

Exception in thread "main" java.lang.IllegalStateException: Failed to find system mod: minecraft
    at MC-BOOTSTRAP/[email protected]/net.minecraftforge.fml.loading.ModSorter.detectSystemMods(ModSorter.java:181)
    at MC-BOOTSTRAP/[email protected]/net.minecraftforge.fml.loading.ModSorter.buildUniqueList(ModSorter.java:145)
    at MC-BOOTSTRAP/[email protected]/net.minecraftforge.fml.loading.ModSorter.sort(ModSorter.java:53)
    at MC-BOOTSTRAP/[email protected]/net.minecraftforge.fml.loading.moddiscovery.ModValidator.stage2Validation(ModValidator.java:98)
    at MC-BOOTSTRAP/[email protected]/net.minecraftforge.fml.loading.FMLLoader.completeScan(FMLLoader.java:172)
    at MC-BOOTSTRAP/[email protected]/net.minecraftforge.fml.loading.FMLServiceProvider.completeScan(FMLServiceProvider.java:91)
    at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.TransformationServiceDecorator.onCompleteScan(TransformationServiceDecorator.java:174)
    at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.TransformationServicesHandler.lambda$triggerScanCompletion$24(TransformationServicesHandler.java:145)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
    at java.base/java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1779)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
    at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:575)
    at java.base/java.util.stream.AbstractPipeline.evaluateToArrayNode(AbstractPipeline.java:260)
    at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:616)
    at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:622)
    at java.base/java.util.stream.ReferencePipeline.toList(ReferencePipeline.java:627)
    at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.TransformationServicesHandler.triggerScanCompletion(TransformationServicesHandler.java:147)
    at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.Launcher.run(Launcher.java:95)
    at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.Launcher.main(Launcher.java:78)
    at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26)
    at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23)
    at [email protected]/cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:141)

> Task :runClient FAILED

Deprecated Gradle features were used in this build, making it incompatible with Gradle 9.0.

You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins.

See https://docs.gradle.org/8.1.1/userguide/command_line_interface.html#sec:command_line_warnings
10 actionable tasks: 8 executed, 2 up-to-date

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':runClient'.
> Process 'command 'C:\Program Files\Eclipse Adoptium\jdk-17.0.8.7-hotspot\bin\java.exe'' finished with non-zero exit value 1

 

Just eyeballing it, it looks like somehow my project has not loaded any base-level minecraft assets? Which doesn't make sense since, again, I followed the tutorial to the letter. But my experience modding in the Forge ecosystem is very limited. Any help or suggestions would be appreciated. I thought it was because I didn't have a forge client installed for this version in my minecraft launcher so I installed that, reloaded Gradle in IntelliJ but same error.

 

Using:
IntelliJ IDE

Eclipse Adoptium JDK 17.0.8.7

Forge MDK (and client install) 1.20.1-47.1.43

Windows 10 x64

 

Sounds like they either didn't tell you how to setup your project correctly, or you missed a step. Go back and retrace your steps, or perhaps try another tutorial series.

I prefer McJty's stuff myself, I check them out every couple versions in addition to reading the MC code in my IDE.

https://www.mcjty.eu/docs/1.20

I use to get this error if my mod ID didn't follow the namespace rules.
No capticals, no spaces, no special characters, just lower case and underscores.

Change your MODID, and make sure it matches in your main class as well as meta-inf/mods.toml

5 hours ago, JCox said:

I use to get this error if my mod ID didn't follow the namespace rules.
No capticals, no spaces, no special characters, just lower case and underscores.

Change your MODID, and make sure it matches in your main class as well as meta-inf/mods.toml

I will try that when I get a chance, I did use a "-" but I thought that was allowed. Will update the post when I try that. Thanks!

26 minutes ago, Armand Jackson said:

I will try that when I get a chance, I did use a "-" but I thought that was allowed. Will update the post when I try that. Thanks!

Holy hell that fixed it, I replaced the "-" with a "_" and everything is working. Now I know, thank you very much!