check every few seconds

I have a custom function which adds status effects to the player. currently want to call that function at least every few seconds to make sure the player has the item in inventory. I tried overriding onUpdate() for this but the game crashes. Is there some other way of doing this? Thanks in advance

this is my function:

	public void buff(EntityLivingBase play, int duration) {
		if ( play.getHeldItemOffhand().getItem() == play.getHeldItemMainhand().getItem() ) {
			int boost = 3;
			
			play.addPotionEffect(new PotionEffect(MobEffects.SPEED, duration, boost));
			play.addPotionEffect(new PotionEffect(MobEffects.FIRE_RESISTANCE, duration, boost));
			play.addPotionEffect(new PotionEffect(MobEffects.RESISTANCE, duration, boost));
			
		}
	}