quick java help

having issues with this bit of java code:

  JOptionPane.showMessageDialog(null, "First line.",acctStr  +
                                                          "\n Second line.",nameStr +   
                                                          "\\n Your total for regular service is $%.2f  %n",regtotal );
             

showMessageDialog is red saying that The method showMessageDialog(Component, Object, String, int, Icon) in the type JOptionPane is not applicable for the arguments (null, String, String, String, double)
 i need to have a j option multi line output, but its not just text, some are also variables, what code am i missing?

I call sloppy seconds on the goat when >>7-kun is done.