//...
/** Start GUI */
JFrame f = new JFrame("Customized buttons");
JPanel wrapPan = new JPanel();
wrapPan.setBackground(new Color(0xFFFFFF));
f.getContentPane().add(wrapPan,"Center");
LayoutManager layWrap = new FlowLayout();
wrapPan.setLayout(layWrap);
/** The wished work */
JButton but1 = new JButton("my button");
wrapPan.add(but1, BorderLayout.CENTER);
/** End GUI */
f.setSize(new Dimension(300,100));//f.setBounds(50, 50, 200, 100);
f.setVisible(true);
//...