John is a senior engineer of the Building Department of the Hong Kong SAR government. From time to time, he is always short of money because he likes gambling very much. At the end of a month, he will borrow several hundred dollars from David, a junior engineer under the supervision of John. John also asks David to buy coffee and sandwich for him two to three times every month. John will repay the money to David after he has received the salary at the end of the month. David has never refused the request of David as he does not want to offend John.

Has John committed any offence under the Prevention of Bribery Ordinance?