Neither the Sun nor Jupiter are "solid" masses.  

Speed of impact will make a huge difference.  In a very slow impact, the Sun absorbs Jupiter with little more than a hiccup.  

Though I could see the sun having some flares and CMEs.  If they are pointed at the Earth, the effects will range anywhere from a mild increase in the ionization of the ionosphere (better short wave communications) to a game over blast of high energy particles (kills all ungrounded/shielded electronics and electrical systems).

In a high speed impact will likely eject some mass, again the direction of this is everything.  

I think @bowlturner has a [serious point][1].  Jupiter *passing* the Earth (with its intense magnetic field) could be a huge problem in its own right.  Fortunately, space, even in the inner system, is BIG.  Lots of room to slip Jupiter past us.


  [1]: https://worldbuilding.stackexchange.com/questions/3665/how-solar-activity-will-change-if-impacted-by-a-planet#comment7671_3668