Upvote:7
They often cancel your existing US visas when you apply for a US visa, but not always. In other words, it is possible to have two valid US visas in your passport at the same time. For example, if you apply for a work visa but have plans to have a brief visit before you start work, then you can keep your visitor visa along with the work visa. Maybe your situation is similar, with the short J1 program.
In any case, if they cancelled it, you would know -- it will be written in big letters on the visa. From your description, they did not cancel your B1/B2 visa. The reason why they did not cancel it is not important. Your B1/B2 visa is still valid and you can use it.