Musician J.J. Cale, singer and author of the iconic songs “After Midnight” and “Cocaine,” died Friday of a heart attack. He was 74. Originally from Oklahoma, Cale, a self-taught guitarist, had struggled as a musician until “After Midnight” was picked up by Eric Clapton in 1970. Cale said that after he heard it, he thought “Oh man, I might stay with the music business.” Cale was famously publicity-shy, not appearing on his own album covers for 15 years and turning down an invitation to the Oklahoma Music Hall of Fame. Cale’s songs have been covered not only by Clapton but also Waylon Jennings, Carlos Santana, and Randy Crawford. The musician Beck has said Cale influenced his work.