Probier es mal so:
Object[] message = {"IP-Adress", "IP-Adress",
"Netmask", "Netmask",
"Gateway", "Gateway",
"Host-Adress", "Host-Adress",
"Broadcast", "Broadcast",
"SN-Product", "SN-Product",
"SN-Ws-Main", "SN-Ws-Main",
"SN-Ws-Main-IdX","SN-Ws-Main-IdX",
"Sn-Coil", "Sn-Coil",
"Sn-Coil-IdX", "Sn-Coil-IdX",};
JOptionPane pane = new JOptionPane(message,JOptionPane.PLAIN_MESSAGE,JOptionPane.OK_CANCEL_OPTION);
JDialog dialog = pane.createDialog(null, "Change Ip");
dialog.show();
Object selectedValue = pane.getValue();
if(selectedValue instanceof Integer)
System.out.println(((Integer)selectedValue).intValue());
else
System.out.println("null");
EDIT: da war jemand schneller -.-