adding events to random buttons of the keyboard

Hello guys i really need your help . I want to make some program in javafx so i need to add listener to random generated button on the keyboard. For example :

i don't want to add some action if user type enter but i want to add action to some random button and nobody would know which is that button . so the user need to click every single button on the keyboard to find out which is that button.How would he knows that this is the correct button ? - > well the program will be executed , when he click on the wrong button -> nothing will happen.