NXT lejos let 2 motors move at the same time

In case somebody is as crazy as me and comes across this in 2019 or later:
The

Motor.A.rotate(xy)

command blocks the processor, so

Motor.B.rotate(xy)

means, the motor B does the rotation xy on top while A is already halted. (At least my system does this...)

My code, I hope i can help someone:

Motor.A.forward();
Motor.B.forward(); //Both motors start turning
Motor.A.rotate(xy); //Both Motors turn, until A has covered the whole distance (relative)
Motor.B.stop();
Motor.A.stop(); //Both Motors halt

If you want both Motors to travel different distances e.g. with different speed, I'm sorry, I can't help you, but try to do some tricky calculations...