A customer demonstrates two cans of soda drink he bought via self-service checkout in an unmanned supermarket in Qingdao, east China's Shandong Province, Sept. 13, 2014. The supermarket consists only of auto retailing machines which accept self-assisted payments by bank notes, coins or quick response (QR) codes. (Xinhua/Wang Haibin)

A customer gets his smartphone ready for QR code payment in an unmanned supermarket in Qingdao, east China's Shandong Province, Sept. 13, 2014. The supermarket consists only of auto retailing machines which accept self-assisted payments by bank notes, coins or quick response (QR) codes. (Xinhua/Wang Haibin)

A young customer buys drinks via self-service checkout in an unmanned supermarket in Qingdao, east China's Shandong Province, Sept. 13, 2014. The supermarket consists only of auto retailing machines which accept self-assisted payments by bank notes, coins or quick response (QR) codes. (Xinhua/Wang Haibin)

Customers use QR code scanning to pay for their shopping bill in an unmanned supermarket in Qingdao, east China's Shandong Province, Sept. 13, 2014. The supermarket consists only of auto retailing machines which accept self-assisted payments by bank notes, coins or quick response (QR) codes. (Xinhua/Wang Haibin)