It should be interesting. When Kim Il Sung died (early 90s?) he had annointed Kim Jong Il as successor. At that time Kim Jong Il had spent a lot of time with the military and was fairly well respected by the generals in the army who had served under Kim Il Sung.
While it appears that there have been attempts to groom "the young 'Un" (Great line, Spider. I have plans to steal it, without citation, in as many applications as possible.), from what I have read he has not received the acceptance of the military elite. Again, from what I have read, it would appear he is seen as somewhat of a dilettante. It will be interesting to see if he can consolidate power, keep the "war lords" happy, and continue the line of succession. The idea of a nuclear power going through a palace revolt is a little scary.