class  t1 {
    LDialog lDialog;
     int  m =  1 ;

     public  t1 () {
        lDialog =  new  LDialog( this );
        lDialog.pack();
        lDialog.setVisible(true);
    }

     public   void  m1() {
        System.out.println(m);
    }
}

 import  javax.swing.*;
 import  java.awt.event.ActionListener;
 import  java.awt.event.ActionEvent;

 public   class  LDialog  extends  JDialog {

    t1 obj;

     public  LDialog(t1 objp) {
         this .obj = objp;
        JButton but =  new  JButton("Test");
         this .getContentPane().add(but);
        but.addActionListener( new  ActionListener() {
                 public   void  actionPerformed(ActionEvent e) {
                     obj.m1();
                }
            }
        );
    }
}