DarkLions

So I have found out what the problem was. The Overworlddimension has overwrite the defaultBlock value. Because the value is in the constructor defined, I can‘t change it directly. or is impossible to change. The best is I just create a custom Dimension and settings. Thank you for your support :D

Thanks for your reply. The code is seperated from the main class and it will called if the "FMLLoadCompleteEvent" is fired. I have tried (Class GenClass = GenerationSettings.class) seem also not working. So have tried to implement the ObfuscationReflectionHelper, but I get the same issue. It isn't changing anything. I'm not sure, if it is because I call a newInstance for the object. the code in his own class: (only changed the class.getDeclaredField to ObfuscationReflection) package com.darklions.testmod.world.gen; import java.lang.reflect.Field; import java.lang.reflect.Modifier; import com.darklions.testmod.objects.items.StickOfDebug; import net.minecraft.block.Blocks; import net.minecraft.world.gen.GenerationSettings; import net.minecraftforge.fml.common.ObfuscationReflectionHelper; public class VanillaGenSettingsOverride { public static void overrideSettings() { try { Class<?> GenClass = GenerationSettings.class; //used this method instead of GenClass.getDeclaredField Field defaultBlockField = ObfuscationReflectionHelper.findField(GenClass, "defaultBlock"); GenerationSettings gen = (GenerationSettings) GenClass.newInstance(); Field modifiers = Field.class.getDeclaredField("modifiers"); modifiers.setAccessible(true); modifiers.setInt(defaultBlockField, defaultBlockField.getModifiers() & ~Modifier.FINAL); defaultBlockField.set(gen, Blocks.DIAMOND_BLOCK.getDefaultState()); //this give me the diamond_block value StickOfDebug.s = new String(defaultBlockField.get(gen).toString()); } catch(Exception e) { StickOfDebug.s = new String(e.toString()); } } } @SubscribeEvent public static void loadCompleteEvent(FMLLoadCompleteEvent event) { CustomOreGen.setupOverWorldOreGeneration(); CustomOreGen.setupEndOreGeneration(); CustomOreGen.setupNetherOreGeneration(); CustomWorldCarverGen.setupEndCarverGeneration(); VanillaGenSettingsOverride.overrideSettings(); } And this is in the main class.

(I apologize for bad english) Hello, I have tried to overwrite the vanilla GenerationSettings using Java.Reflection. Settings override class: (This code will run, if the LoadCompleteEvent fire) public static void overrideSettings() { try { Class<?> GenClass = Class.forName("net.minecraft.world.gen.GenerationSettings"); Field defaultBlockField = GenClass.getDeclaredField("defaultBlock"); GenerationSettings gen = (GenerationSettings) GenClass.newInstance(); defaultBlockField.setAccessible(true); Field modifiers = Field.class.getDeclaredField("modifiers"); modifiers.setAccessible(true); modifiers.setInt(defaultBlockField, defaultBlockField.getModifiers() & ~Modifier.FINAL); defaultBlockField.set(gen, Blocks.DIAMOND_BLOCK.getDefaultState()); StickOfDebug.s = new String(defaultBlockField.get(gen).toString()); } catch(Exception e) { StickOfDebug.s = new String(e.toString()); } } The Field with the "defaultBlock" have been successfully overwritten and the field give me the diamond_block and I don't get any exception. But when I generate a new world, the defaultBlock is still stone_block. If I using the my Debug_Stick, the GenerationSettings still give me the stone_block value back. The debug stick class: public class StickOfDebug extends Item { public static String s = ""; public StickOfDebug(Properties properties) { super(properties); } @Override public ActionResult<ItemStack> onItemRightClick(World worldIn, PlayerEntity playerIn, Hand handIn) { ItemStack itemstack = playerIn.getHeldItem(handIn); if(worldIn.isRemote) { return ActionResult.resultPass(itemstack); } else { playerIn.sendMessage(new StringTextComponent(s)); try { Class<?> genClass = Class.forName("net.minecraft.world.gen.GenerationSettings"); GenerationSettings gen = (GenerationSettings) genClass.newInstance(); Field field = genClass.getDeclaredField("defaultBlock"); field.setAccessible(true); playerIn.sendMessage(new StringTextComponent(field.get(gen).toString())); } catch (Exception e) { e.printStackTrace(); } return ActionResult.resultSuccess(itemstack); } } } I would appreciate if someone could help me.