Question about singleton design pattern...bean scopes of spring ...what is default bean scope on spring....give example for prototype bean scope and deafault bean scope....question about connection pooling ...how to create connection poling ...what is atomic transaction ...more questions on spring ....ioc container .....how to create api like @transactional annotation....implement transactional class....internal implementation on comparable and comparable interface ....design transactionals....how to handle the error in application....deep concepts about spring and Java ....level was very high ...not like service based companies ....prepared well for the interview...