java.lang.NullPointerException: Initializing game


public class RegisterItemRender {

	public static void registerItems() {
		registerItem(JerrysMod.JerrySword);

and all other items...
	}

	private static void registerItem(Item item) {
		//ModelLoader.setCustomModelResourceLocation(item, 0, new ModelResourceLocation(Reference.MOD_ID + item.getUnlocalizedName(), "normal"));
		Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, 0, new ModelResourceLocation(Reference.MOD_ID + ":" + item.getUnlocalizedName(), "normal"));

	}

}