Setting Mnemonics and Hot Keys for a JOptionPane Dialog

You can create your JOptionPane, and then loop through the components of the pane (children etc.) checking to see if any components are instanceof JButton, and if so check the text, and set the proper mnemonic.

JOptionPane p = new JOptionPane();
Component[] c = p.getComponents();

Make use of UIManager as follows:

UIManager.put("OptionPane.okButtonMnemonic", "79");  // for Setting 'O' as mnemonic
UIManager.put("OptionPane.cancelButtonMnemonic", "67"); // for Setting 'C' as mnemonic