From the JDK API JOption

     JOptionPane pane = new JOptionPane(arguments);
     pane.set.Xxxx(...); // Configure
     JDialog dialog = pane.createDialog(parentComponent, title);
     dialog.show();
     Object selectedValue = pane.getValue();
     if(selectedValue == null)
       return CLOSED_OPTION;
     //If there is not an array of option buttons:
     if(options == null) {
       if(selectedValue instanceof Integer)
          return ((Integer)selectedValue).intValue();
       return CLOSED_OPTION;
     }
     //If there is an array of option buttons:
     for(int counter = 0, maxCounter = options.length;
        counter < maxCounter; counter++) {
        if(options[counter].equals(selectedValue))
        return counter;
     }
     return CLOSED_OPTION;


JOptionPane.showMessageDialog(
    this, 
    "MessageText.", 
   "DialogTitle", 
   JOptionPane.WARNING_MESSAGE
);