How to set background color of a button in Java GUI?

Question

Below is the code which creates 9 buttons in gridlayout form on a specific pannel3. What i want is to make the background of each button black with grey text over it. Can a

Answer 1

Simple:

btn.setBackground(Color.red);

To use RGB values:

btn[i].setBackground(Color.RGBtoHSB(int, int, int, float[]));