You mean Goku? Yes, from his adoptive grandfather Gohan; Goku isn't even human, so Gohan was not his biological grandfather.
because dragonball z is a Japanese
It depends on what kind of martial arts. In Taekwondo, the founder was Eternal Grand Master H.U. Lee.
karate
by sagas if you see a dragonball somewhere or by winning martial arts tournaments
Developing character.
Salman Khan is an Indian film actor who learned martial arts for some of the roles he played in movies.
Jackie Chan's Stuntmaster
Jackie Chan Stuntmaster
it is thought to be the first martial art. the Monks learned this and then came up with Kung Fu and so on and so on....
Chuck Norris learned Tang Soo Do while stationed in Korea with the US Air Force.
Jackie Chan learned martial arts because his father taught him when he was very young and later it was because it was part of the curriculum at the Peking Opera School so he had to learn it. After leaving school and entering the movies as a stunt man Jackie learned different martial art skills for the movies.
No, Jackie Chan did not study formal martial arts. He was studying in acting school and learned things there.