Item names aren't showing properly

I have like 100 items in my mod. All the blocks are showing their name right. But all the items doesn't. I tried to change the pack.mcmeta file but it changes the value to 3 every time i save. 

They aren't even showing in the lang files, the script seems to be right.

Example script of one item:

package mod.mcreator;

import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.common.registry.ForgeRegistries;
import net.minecraftforge.fml.common.event.FMLServerStartingEvent;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
import net.minecraftforge.fml.common.event.FMLInitializationEvent;

import net.minecraft.world.World;
import net.minecraft.item.ItemStack;
import net.minecraft.item.Item;
import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.client.renderer.block.model.ModelResourceLocation;
import net.minecraft.client.Minecraft;
import net.minecraft.block.state.IBlockState;
import net.minecraft.block.Block;

import java.util.Random;

public class mcreator_amber {

	public static Item block;
	public static Object instance;
	static {
		block = (new ItemCustom());
	}

	public void load(FMLInitializationEvent event) {
		if (event.getSide() == Side.CLIENT) {
			Minecraft.getMinecraft().getRenderItem().getItemModelMesher()
					.register(block, 0, new ModelResourceLocation("testenvironmentmod:amber", "inventory"));
		}
	}

	public void generateNether(World world, Random random, int chunkX, int chunkZ) {
	}

	public void generateSurface(World world, Random random, int chunkX, int chunkZ) {
	}

	public void serverLoad(FMLServerStartingEvent event) {
	}

	public void preInit(FMLPreInitializationEvent event) {
	}

	public void registerRenderers() {
	}

	public int addFuel(ItemStack fuel) {
		return 0;
	}

	public static class ItemCustom extends Item {

		public ItemCustom() {
			setMaxDamage(0);
			maxStackSize = 64;
			setUnlocalizedName("amber");
			setRegistryName("amber");
			setCreativeTab(CreativeTabs.MISC);
			ForgeRegistries.ITEMS.register(this);
		}

		@Override
		public int getItemEnchantability() {
			return 0;
		}

		@Override
		public int getMaxItemUseDuration(ItemStack par1ItemStack) {
			return 0;
		}

		@Override
		public float getDestroySpeed(ItemStack par1ItemStack, IBlockState par2Block) {
			return 1F;
		}
		// TODO: use hitx, not player's loc
	}
}