Minecraft examplemod doesn't start in eclipse

[AstroDaFloof]

Im very new to minecraft modding and I basicly have 0 experience with coding.
I setup my eclipse workspace and everything seems to be working. I try running the example mod (without changing a single bit of code) but it cant start the game and just gives me this error. Any help on how to fix this?

Exception in thread "main" java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')
    at net.minecraftforge.gradle.GradleStartCommon.searchCoremods(Unknown Source)
    at net.minecraftforge.gradle.GradleStartCommon.launch(Unknown Source)
    at GradleStart.main(Unknown Source)