( CM ) - Rapper LL COOL J has stirred up trouble with his former record label boss, JAY-Z, by insisting the departing Def Jam president failed his artists. The rap veteran has one more Def Jam release on his contract before he quits the label too. But, before he leaves, he's keen to let the industry know what he thinks about the 99 Problems hitmaker. Speaking out about the music mogul in Sister 2 Sister magazine, LL Cool J says, "It's been a great business for him, but it has been not so great for a lot of the artists that were there (at Def Jam) previously. "We have to be very careful when we talk about it because, for some strange reason, his fans... start thinking, like, you're hating when you're just being real." LL Cool J allso suggests Jay-Z was only given the Def Jam top job because the label's top executives wanted "to show the world that they still cared about hip-hop and they felt like giving him the job would show the world that." Jay-Z quit his post as president of Def Jam Records in December (07) and was alleged to be planning to start his own venture on another label.