It would be impossible for humans or any other life to live on Jupiter, as the planet is made up primarily of gases almost the all the way to its core. NASA speculates that it might be possible for a very secure spacecraft to visit Jupiter, but it couldn't land, as the planet does not have any solid surfaces.
As of 2014, it would also take an incredibly long time for a spacecraft to even visit the planet considering the current technology that is available.
Due to a number of different factors, Mars is considered to be the next most habitable planet in the solar system. One of the reasons is its distance from the sun, which makes it fall within the temperature range that could possibly support life. The rest of the planets in the solar system are either far too hot or far too cold. For instance, despite the fact that Venus is the next closest planet to Earth after Mars, the temperature on its surface surpasses 400 degrees Fahrenheit. The pressure on Venus is also too much for a human to sustain, as it is the equivalent of being 900 meters below the ocean on Earth, whereas the gravity on Mars is only 38 percent of that on Earth.