# Import Java packages include Java import javax.swing.JFrame frame = JFrame.new("Hello Swing") button = javax.swing.JButton.new("Klick Me!") button.add_action_listener do |evt| javax.swing.JOptionPane.showMessageDialog(nil, <Hello from JRuby.
Button '#{evt.getActionCommand()}' clicked. EOS end # Add the button to the frame frame.get_content_pane.add(button) # Show frame frame.set_default_close_operation(JFrame::EXIT_ON_CLOSE) frame.pack frame.visible = true