Elementa UI Library Not Working - NoClassDefFoundError when Opening WindowScreen in Forge 1.20.1

[xI-Mx-Ix]

I am encountering an issue when trying to open a WindowScreen in Forge 1.20.1 using the Elementa UI library. Every time I attempt to do so, I get the following error:

Caused by: java.lang.NoClassDefFoundError: gg/essential/elementa/WindowScreen Caused by: java.lang.ClassNotFoundException: gg.essential.elementa.WindowScreen

I’ve tried several versions of Elementa as well as UniversalCraft, but the issue persists.

The WindowScreen should open without any issues, without throwing the NoClassDefFoundError.

• Minecraft Version: 1.20.1
• Forge Version: 47.4.0
• Elementa Version: every version
• UniversalCraft Version: every version
• Java Version: 17

Note: I am using Java for my mod development, even though the Elementa library is written in Kotlin.

I also searched for Forge versions in Maven, but whenever I used them, I encountered the same error. Additionally, when I tried using fg.deobf, it didn't work either because the Forge versions didn’t have a mods.toml file.

[Deftu]

Are you experiencing this crash/error in production or in the developer environment?

[xI-Mx-Ix]

in development environment

[xI-Mx-Ix]

Elementa 695 is a Fabric mod and cannot be loaded in Forge. I tried a Forge version (1.18.1), and it loaded successfully:

implementation(fg.deobf("gg.essential:elementa-1.18.1-forge:657"))
implementation(fg.deobf("gg.essential:universalcraft-1.20.1-forge:381"))

But the same error occurred.The Forge classloader can't find it for some reason.