[1.12.2]Register custom item model from block

I have a problem about register custom item model from block.Everything is good in the eclipse, but when I run it, it always crashes.

A part of the crash report:

Quote

Caused by: java.lang.NullPointerException
    at net.minecraft.client.renderer.block.model.ModelResourceLocation.<init>(ModelResourceLocation.java:24)
    at eling.schoolcity.common.block.BlockLoader.Initmodel(BlockLoader.java:28)
    at eling.schoolcity.client.ClientProxy.preInit(ClientProxy.java:15)
    at eling.schoolcity.schoolcity.preInit(schoolcity.java:34)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

BlockLoader.java :

package xxx.xxx.common.block;

import net.minecraft.block.Block;
import net.minecraft.client.renderer.block.model.ModelResourceLocation;
import net.minecraft.item.Item;
import net.minecraft.item.ItemBlock;
import net.minecraftforge.client.model.ModelLoader;
import net.minecraftforge.fml.common.registry.ForgeRegistries;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.relauncher.SideOnly;

public class BlockLoader
{
	public static Block blockXxxx = new BlockXxxx().setUnlocalizedName("xxxx");

	public void init()
	{
		ForgeRegistries.BLOCKS.register(blockXxxx.setRegistryName("xxxx"));
		ForgeRegistries.ITEMS.register(new ItemBlock(blockXxxx).setRegistryName(blockXxxx.getRegistryName()));    //←The Line 28

		}
	
	@SideOnly(Side.CLIENT)
	public static void clientInit() 
	{

		ModelLoader.setCustomModelResourceLocation(Item.getItemFromBlock(blockXxxx), 0, 
				new ModelResourceLocation(blockXxxx.getRegistryName(), "inventory"));

	}
}

Thanks.

Edited October 5, 20196 yr by Eling
Thanks.