WARNING THIS POST HAS MAJOR SPOILERS!!!! SCROLL DOWN FOR CONTENT!!!!
If your still here chances are you've seen Force Awakens. As you know, Han Solo is killed by his son Kylo Ren. My theory is that Han Solo is a Jedi and He sacrificed himself for his son.
First of all, How could Han's and Leia's son be so strong with the force if only one has the potential to be a Jedi. Their son should only have half the strength that he does if Han isn't force sensitive.
Second, Han Solo sacrificed himself for his son. One of his lines was that he would do anything for his son. He would even sacrifice himself. He probably knew what will happen to the future, which brings me to my final point.
Finally, why would Han pretty much commit suicide unless he knew he would live on through the force. Also, you know how Kylo wants to follow in Darth Vader's footsteps? Remember in the sixth movie Vader goes to the light side. This leaves us to assume that the same will happen to Kylo. Han can know all this because force. He even said to Rey on the ship, the force is real and it surrounds everything.
Hope you like this and find it interesting. Please try and find flaws in this so I can improve.