Use forge events in forgeInit.kt, and add a @JvmStatic annotation to the logger in Snowy.kt

common/src/main/kotlin/fr/username404/snowygui/Snowy.kt

@@ -5,6 +5,7 @@ import org.apache.logging.log4j.Logger
 
 abstract class Snowy {
     companion object {
+        @JvmStatic
         val logs: Logger = LogManager.getLogger("Snowy")
     }
     fun atInit() {

forge/src/main/kotlin/fr/username404/snowygui/forge/forgeInit.kt

@@ -5,13 +5,16 @@ import fr.username404.snowygui.config.SnowyConfigScreen
 import net.minecraftforge.fml.ExtensionPoint
 import net.minecraftforge.fml.ModLoadingContext
 import net.minecraftforge.fml.common.Mod
+import net.minecraftforge.fml.event.lifecycle.FMLClientSetupEvent
+import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent
+import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext
 import java.util.function.BiFunction
 import java.util.function.Supplier
 
 @Mod("snowygui")
 class ForgeInit: Snowy() {
-    init {
+    private fun initSetup(event: FMLCommonSetupEvent) = atInit()
-        atInit()
+    private fun configSetup(event: FMLClientSetupEvent) {
         ModLoadingContext.get().registerExtensionPoint(
             ExtensionPoint.CONFIGGUIFACTORY,
             Supplier {
@@ -23,4 +26,10 @@ class ForgeInit: Snowy() {
             }
         )
     }
+    init {
+        with(FMLJavaModLoadingContext.get().modEventBus) {
+            addListener(this@ForgeInit::initSetup)
+            addListener(this@ForgeInit::configSetup)
+        }
+    }
 }