You'd think there was a Jennifer Lopez convention going on -- Marc Anthony, Casper Smart and Alex Rodriguez were all chilling in Hollywood and WeHo Wednesday night.
J Lo's exes -- Marc and Casper -- were actually at the same restaurant, Viva Hollywood, checking out some "f**king dope" music ... as Marc put it. Meanwhile, A-Rod did dinner at Craig's just a few miles away.
Jennifer wasn't around -- probably less drama that way -- but she was the hot topic.