Why did Shakespeare call Hamlet Hamlet?

Answer 1

The story of Hamlet was around long before Shakespeare and in the form given to it by Belleforest was published about thirty years before Shakespeare wrote his play. The story had most likely previously been turned into a play. In all cases, the main character's name was Hamlet, which is why Shakespeare used this name for his play. It has nothing to do with Shakespeare's son. A play about an American President assassinated in a theatre by a guy called Booth would not be called Lincoln because the playwright had a son of that name.