how does one transfer from san jose state to berkeley without losing any precious credits?

Berkeley will decide which credits are transferable, and which are not. You can usually find out what course units are transferable beforehand, so that you don't spend time and money taking units that won't transfer. Talk to an academic counselor at SJ State, or talk to an admissions counselor at Berkeley.

Normally, general education credits that cover the same coursework at both colleges will be transferable.