June 25, 1999 | Adam Sandler tries to have the best of both worlds - and, to a large degree, succeeds - in Big Daddy, a comedy that balances the happy-puppy sentiment of The Wedding Singer with the broad-as-a-barn silliness of The Waterboy. And while it may strike you as a bit early in Sandler's career for a greatest-hits compilation, the new movie is considerably more than the sum of it second-hand parts.

Big Daddy finds Sandler perfectly cast as Sonny Koufax, a 32-year-old law school graduate who has never gotten around to taking his bar exam. Indeed, he hasn't gotten around to very much at all during a life of self-indulgent slackerdom. Sonny doesn't need to work, thanks to his crafty investment of an insurance settlement. But Vanessa (Kristy Swanson), his long-time girlfriend, thinks there is more to life than sleeping late, lunching on breakfast cereal and watching TV until it's time to order take-out.

While Kevin (Jon Stewart), Sonny's more goal-oriented roommate, is out of the country on business, a 5-year-old boy is dropped off at their apartment. Julian (played variously by twins Cole and Dylan Sprouse) apparently is the product of Kevin's long-ago one-night stand with a woman who no longer can care for the child. Sonny obligingly takes charge of the situation - and decides to adopt Julian. That way, he figures, he will demonstrate to Vanessa that he really is a mature and responsible grown-up.

Unfortunately, when Sonny brings Julian over to Vanessa's apartment, she's already entertaining a new boyfriend. And when Sonny tries to return Julian to the child-welfare authorities, he's told that the boy will be stuck in an orphanage until a suitable foster family can be found. So Sonny agrees to keep Julian for a little while. But not for long. Just temporarily. Not permanently. Yeah, right.

The makers of Big Daddy are quite shameless in their yanking of heartstrings as Sonny becomes a better person through his misadventures in child rearing. Fortunately, the movie is too funny, and Sandler is too ingratiating, for you to mind the manipulation. Big Daddy generates so much good will during its first hour or so that you stick with it even during the inevitable shift into tearjerking as the bad old social workers try to reclaim Julian, and Sonny must clean up his act to defend himself in a courtroom encounter.

There is something gleefully subversive about the family values upheld in much of the movie's first half, as Sonny teaches Julian how to pee against walls, trip unwary Rollerbladers, make a meal from ketchup packets - in short, how to be just like Sonny. And when Sonny is encouraged to become a better father after being strongly discouraged from parenting by his own disapproving dad (Joe Bologna), it becomes all the more obvious that, bless his heart, Sonny is just a big kid himself. All he really needs to grow up is the chance to be someone else's daddy.

Under the gracefully unobtrusive direction of Dennis Dugan (who also led Sandler through his paces in Happy Gilmore), Big Daddy is a star vehicle that has more than enough room to accommodate some fine work by a first-rate supporting cast. Joey Lauren Adams is disarmingly charming as Layla, the smiley sweetheart who brings out the best in Sonny, while Rob Schneider (as an English-mangling take-out-food delivery guy) and Steve Buscemi (as a homeless man with a fondness for breakfast sandwiches from McDonald's) are reliably wacky scene-stealers. There are cheap laughs here and there, and a couple of grotty gross-out gags. More often, however, Big Daddy is uncommonly sweet-natured and warm-hearted in its approach to making audiences giggle.