What 'technology' would we need to obtain to land on planet Jupiter ?

Jupiter is a gas giant - but that can be misleading. You cannot simply fly though Jupiter like flying through a cloud. The bulk of Jupiter consists of hydrogen. The deeper you into the atmosphere, the denser the hydrogen becomes, and the hotter it gets due to nuclear fission reactions (radioactivity) that heat the core. Eventually you would be diving through a hot liquid hydrogen soup. The Galileo spacecraft launched a probe that fell through Jupiter's atmosphere. It only fell about 150 miles before it was destroyed. The conditions are not conducive to life support.