For a few hours Saturday night, the center of the “Star Wars” universe was in Newark, N.J., as director J.J. Abrams took some time away from putting the finishing touches on “The Force Awakens” to help Stephen Colbert raise money for one of the “Late Show” host’s favorite causes.

Before the main show, a geeky chat in front of a couple thousand fans and patrons at the N.J. Performing Arts Center, Abrams told a smaller crowd munching mini lobster tacos and sipping Brooklyn Lager at a reception that he had just finished the final...