The funny thing is that in the old days, it is required to know how the machine worked - you coded assembly against physical memory.

But that was incredibly hard, and error prone (and comes with tonnes of limitations). The fact that today, it's very easily possible to write working programs without knowing any of the underlying details, is a marvel.

If i were to hire a truck driver, i wouldn't expect to have to ask him to understand how the truck itself worked (e.g., fuel injection when he presses the accelerator). He only needs to know how to operate the truck from the interface (steering wheel!). Why isn't this the same for a java programmer?