I know that this is a common topic but I just cant get it to work. I already have tried getContainerItem and getting return with +1 damage. Also my super constructor doesn't seem to work. Here is my code.

public class DamageItem extends Item {
public DamageItem(){
	super();
	setMaxStackSize(1);
	setNoRepair();
	setMaxDamage(20);
}


@Override
    public boolean hasContainerItem(ItemStack stack)
    {
        return true;
    }

    @Override
    public boolean doesContainerItemLeaveCraftingGrid(ItemStack itemstack)
    {
            return true;
    }

    
    public boolean isItemStackDamageable()
    {
        return true; 
    }

    public ItemStack getContainerItemStack(ItemStack itemStack, EntityPlayer player) {


    	itemStack.setItemDamage(this.getDamage(itemStack) + 1);
	return itemStack;

    }

getContainerItemStack(ItemStack itemStack) has changed to getContainerItem(ItemStack itemStack), also make sure to use @Override.

okay changed it but my super constructor is still not working. So I cannot setMaxStack and code not working.

super() and setMaxStackSize() both look fine with the code you provided above. How exactly are they not working?

They are not working means that I cannot set stack size to 1 , I still pick up 64 items in game. Is there anything to do with my main class? There is set the item like -

public static Item damageItem;

Do you in any way in the mod modify the item's stack size after initialization? Search where the setMaxStackSize() method is referenced, you might find something.