No it doesn't.

As I say, the initialiser for jdialog runs *immediately* after super()
returns. Your code prints "MyFrame.constructor" after super() returns,
and after the initialisers have run.

class MyDialog extends javax.swing.JDialog {
    MyDialog(javax.swing.JFrame frame) {
        System.out.println(
            "MyDialog.constructor, frame.title: "+frame.getTitle()
        );
    }
}

class MyFrame extends javax.swing.JFrame {
     private MyDialog mydialog = new MyDialog(this);
     MyFrame() {
         super(print("--- title ---"));
         System.out.println("MyFrame.constructor, after super");
     }
     private static String print(String msg) {
         System.out.println("Print: "+msg);
         return msg;
     }
     public static void main(String[] args){
         new MyFrame();
     }
}

$ java MyFrame
Print: --- title ---
MyDialog.constructor, frame.title: --- title ---
MyFrame.constructor, after super

The title property is set in the JFrame constructor. The MyDialog
constructor reads that property, so must have printed the message after
the JFrame constructor ran.

Tom Hawtin