@Override
			public void windowClosing(WindowEvent arg0) {
				if (client != null) {
					int answer = JOptionPane.showConfirmDialog(null,
							"Do you want to commit?", "Information",
							JOptionPane.YES_NO_OPTION);
					if (answer == 0) {
						if (client.commit()) {
							JOptionPane.showMessageDialog(null,
									"Commit successful!", "Information",
									JOptionPane.INFORMATION_MESSAGE);
						} else {
							JOptionPane.showMessageDialog(null,
									"Commit failled!", "Error",
									JOptionPane.ERROR_MESSAGE);
						}
					}

					client.close();
				}
			}