The full form of J4U is Just For You

“Only for you” implies that it is not okay (or not allowed or not safe) for other people to have it or use it. You can also use “just for you” to mean this, but “only for you” gets the point across better.

“Just for you” implies that the only reason it was made or chosen was because you will like it or because it is exactly right for you.

Just for You is Lionel Richie’s seventh studio album, which was released in March 2004 in the United Kingdom, with the US release in May of that year. Released shortly after Richie’s divorce from his second wife, the album featured Richie in collaboration with singers and musicians from different backgrounds. It received mixed reviews, with much of the criticism targeted at the album’s lyrics. It sold 207,000 copies and peaked at #22 on the American Billboard 200.