Please answer me:
1. What is the difference between CAN Node ID & CAN Message ID? How the CAN Node ID helpful in Communication?
In UDS many services are defined under ISO 15765-2 standard. No, they're not. UDS is defined on top of ISO TP, not the other way round.
Also, UDS implemented over CAN Data Frame. No. The only implementation you've seen is over ISO-TP. That doesn't change the fact that UDS can be implemented on top of other transport protocols, too.
It's ISO TP which, in turn, is based on CAN frames.
When i tried to send UDS sevices, Service ID is transmitted on CAN message ID field. That's either pure coincidence, or a faulty implementation of UDS/ISO-TP, or you've been mislead be the very powerful interpretation features of your CAN inspection program.
Do you think AUTOSAR is good to use, and would be very popular one day? Personally, I dislike AUTOSAR.