Juris http://www.answers.com/topic/juris-doctor#, or doctor of jurisprudence, commonly abbreviated J.D., is the degree commonly conferred by law schools. Read more:...
This depends on your location and the institution you wish to study law at. From what I understand, completing the secondary/high school Legal studies course or it's equivalent is often required.
the doctors study what category they have to study eg:- like dermatoligists have to study the skin and the medicine and treatments in that specific category.