Typical instruments found in jazz groups include brass instruments such as the saxophone, trumpet, French horn and cornet, woodwind instrument such as the clarinet, flute, oboe and bassoon, and string instruments which include bass and 6-stringed guitars, double bass, cello, violin and viola. Jazz vocalists can also be found in some bands. Instrument selection is usually the personal choice of the band leader or director.
Jazz is a very old genre and it is often assumed that only 'old' musicians play jazz music now. However this is not the case, with younger musicians including Victor Wooten of Bela and the Flecktones and the solo pianist Jamie Cullum continuing to both freshen the jazz scene and add to it.
Jazz musicians have some of the most versatile skills in music, including the ability to sight-read (see a previously unknown piece of music and play it within a single reading), improvise (come up with completely original music for the chord changes given), ear-play and know music theory. It is for this reason some of the best jazz players are very well-paid, and learning jazz technique and theory will often allow for learning other genres easily.
I am a jazz musician. I play jazz bass.