Code in Java, please

Write a JavaFX program that is populated with 4 x 4 black buttons in a square. When buttons are clicked, the color of the buttons should change to red in the order they are clicked. Outside of the square, create a button called UNDO. Each time the UNDO button is clicked, the program should undo the color change of the most recently clicked button. In other words, the color of that button would change back to its original black color. The UNDO button can be clicked many times until no button in the square left to be undone.