That depends on the layout that is selected for the container. I don't find the generated code more difficult to read than any other complex layout code. GridBagLayout, GroupLayout, and SpringLayout do involve quite a bit of code and the GUI builder does save a lot time over manually coding it. That said, I agree it is still a good idea for beginners to learn to code it for themselves so they understand the nuances of those layouts.

I misinterpreted the statement. I was thinking like the pre-generated code when creating a new class which some programs just pull from a pre-saved template.

I used to think Netbeans gui code generation was a mess, but once I got used to it it's not so bad. As long as you have planned out ahead of time what the gui will do and you dont have to make too many changes you should be ok.

you're not. The code it generates is impossible to maintain outside Netbeans (which is an immediate disqualifier for any generated code), stinks badly because of all the forced code duplication you're required to have even in your own code that interfaces with it, and has abysmal performance.