Reflexive pronouns are used when the object of the sentence is the same person as the subject. Here, the subject is Johnny and given that he bought something for himself, he is also the object. Although the pronoun himself can sometimes be intensive, this is not the case where it is. Intensive pronoun would be if the sentence said: Johnny himself bought a new basketball.
The pronoun that is used in the given sentence above is the word "himself" which refers to its antecedent "Johnny". "Himself" is an example of a reflexive pronoun. Reflexive pronouns are used when the object of the sentence is the same as the subject. The object is the pronoun "himself" which refers to the subject "Johnny".
