Questions regarding US Exchange Visitor Visa.
From the US State Department Website
The Exchange Visitor (J) non-immigrant visa category is for individuals approved to participate in work-and study-based exchange visitor programs. Participants are integral to the success of the program. Here you can learn more about obtaining the J-1 Visa and other relevant visas.
The J visa is used to allow various people to come to the US for work or study in an exchange based program, which presents unique challenges including those for companies or Universities sponsoring the program as well as for its participants.
J Visa has in addition to various restrictions also may carry a mandatory home country stay before another visa is granted to its participant.