I cant remeber the exact story but, its about a Japenese pilot who shot down an american during WWII.
The Japenese pilot ends up meeting the son of the man he shot down (I think it was an intense fight IIRC) and anyway the son expected to feel anger and hatred towards the IJN pilot, but after talking about the all that had happened and seeing that the IJN pilot was like his father just a man doing his part for his country, they ended up becomming good friends, i beleive that the IJN pilot even stayed at the sons house over christmas(again IIRC).
My point is that i am sure the son would used the term "Jap" on many occasions during his life, but I doubt that he would have used it (at least not in the company of the pilot) once he got to know the man who shot down his father....