java - How to pass value from JInternalFrame to JDialog -

i want know how pass value string jinternalframe jdialog. jdialog child form , jinternalframe parent form. if can please show me simple example.

here code , want pass id productdetails addquantity , tried use static it's not working

public class productdetails extends javax.swing.jinternalframe { string id;     public productdetails() throws exception {         initcomponents(); } //this button go jdialog  private void btnaddquantityactionperformed(java.awt.event.actionevent evt) {                                                        id = txtid.gettext();         addquantity aq = new addquantity(null, true);         aq.setlocationrelativeto(aq);         aq.setvisible(true); } }   public class addquantity extends javax.swing.jdialog {     productdetails pd;     public addquantity(java.awt.frame parent, boolean modal) {         super(parent, modal);         initcomponents();         //i use showmessage show result show me nothing          joptionpane.showmessagedialog(this, pd.id);         txtcurrentid.settext(pd.id);     }     } 

well according me there no specific method u can 1 thing declare data static , u can access static thing dialog box too. u can show there :)

other thing make method input parameters dialog.