IntelliJ IDEA's GUI Designer provides two options for the output:
that are generated when you compile the
project to which they pertain. In this case, the intermediate step of
Java source code is bypassed. Optionally, the compiled classes can be written to
the compiler output directory configured for the project.
Java source code. In that case, all code for the UI components is generated
to the class to which each form is bound.
Refer to the GUI Designer dialog for the detailed description of options.