Java Desktop program

I'm trying to develop a single "from" desktop program that should run on Windows, Linux and Mac. The program should list all the serial ports that are available on the computer and add them to a dropdown list. it will also read some information from a JSON file that will be provided. eventually, the use will select some options from the UI and based on that the program will construct an avrdude command to program a chip through that serial port that was detected. the GUI should be very good looking and pleasing to see. the GUI will ctreated acording to the JSON file all the source code should be submitted with the project