java - 3 Jpanel in JFrame, my button is not visible -

i have jframe 3 jpanel objects. have problem 2 of panels. can see in frame, panel jpanelproduit object panel, jpanelinformations , jpanelventes, see nothing. error?

my code

package ihm;  import javax.swing.*;  import donnees.categories; import donnees.categoriescellrenderer; import donnees.categorieslistmodel; import donnees.marques; import donnees.marquescellrenderer; import donnees.marqueslistmodel; import donnees.produits; import donnees.produitscellrenderer; import donnees.produitslistmodel; import fabriques.fabcategories; import fabriques.fabmarques;  import java.awt.*; import java.sql.connection; import java.sql.drivermanager; import java.sql.sqlexception;  public class fenetre {  static connection conn;      public static void main(string[] args) throws classnotfoundexception, sqlexception {         class.forname("org.hsqldb.jdbcdriver");         conn=drivermanager.getconnection("jdbc:hsqldb:file:bdd/bdd","sa","");          fabcategories.getinstance().demarrerconnexion(conn);         fabmarques.getinstance().demarrerconnexion(conn);          jframe f = new jframe("gestion des produits");         f.setdefaultcloseoperation(windowconstants.exit_on_close);         f.setlayout(new gridlayout(1,2,3, 3));          jpanelproduit jpanelproduit = new jpanelproduit();         jpanelinformations jpanelinformations = new jpanelinformations();         jpanelventes jpanelventes = new jpanelventes();          jpanelproduit.setbackground(color.green);         jpanelproduit.setbackground(color.yellow);         jpanelventes.setbackground(color.pink);          f.add(jpanelproduit);         f.add(jpanelinformations);         f.add(jpanelventes);         f.setsize(700,700);         f.pack();         f.setvisible(true);     } }  class jpanelproduit extends jpanel {      public jpanelproduit() throws sqlexception {         setlayout(new gridlayout(5,2,5,5));          string labelcat = "categories";         string labelmark = "marques";             string labelprod = "produits";           jlist<categories> listcategories= new jlist<categories> ();         jlist<marques> listmarques= new jlist<marques> ();         jlist<produits> listproduits= new jlist<produits> ();          jscrollpane listcategoriesscrollpane = new jscrollpane (listcategories);                  add(new jlabel(labelcat));         add(new jscrollpane(listcategoriesscrollpane));         listcategories.setcellrenderer(new categoriescellrenderer());;         listcategories.setmodel(new categorieslistmodel());          add(new jlabel(labelmark));         jscrollpane listmarquesscrollpane = new jscrollpane (listmarques);                 add(new jscrollpane(listmarquesscrollpane));         listmarques.setcellrenderer(new marquescellrenderer());         listmarques.setmodel(new marqueslistmodel());          add(new jlabel(labelprod));         jscrollpane listproduitscrollpane = new jscrollpane (listproduits);                 add(new jscrollpane(listproduitscrollpane));         //listproduits.setcellrenderer(new produitscellrenderer());         //listproduits.setmodel(new produitslistmodel());      } }  class jpanelinformations extends jpanel {      public jpanelinformations() {         jpanel panelinformation = new jpanel();         setlayout(new gridlayout(7,1,5,5));           jlabel labelinfo = new jlabel ("information");         jlabel labelprix = new jlabel ("prix");         jlabel labeldesc = new jlabel ("description");             jlabel labelquant = new jlabel ("quantite");             jtextfield fieldprix = new jtextfield (20);          jtextarea fielddesc = new jtextarea (20, 20);          jtextfield fieldquantite = new jtextfield (20);           panelinformation.add(labelinfo);         panelinformation.add(labelprix);         panelinformation.add(fieldprix);         panelinformation.add(labeldesc);         panelinformation.add(fielddesc);         panelinformation.add(labelquant);         panelinformation.add(fieldquantite);     } }  class jpanelventes extends jpanel {      public jpanelventes() {         jpanel panelventes = new jpanel();         setlayout(new gridlayout());         jlabel labelvendre = new jlabel ("vendre");         jlabel labelqte = new jlabel ("quantite");         jlabel labelpromo = new jlabel ("promotion");         jlabel labeltot = new jlabel ("total");             jtextfield fieldqte = new jtextfield (20);          jtextfield fieldpromoeuros = new jtextfield (20);          jtextfield fieldpromopourcent = new jtextfield (20);          jtextfield fieldtotal = new jtextfield (20);            panelventes.add (labelvendre);         panelventes.add (labelqte);         panelventes.add (fieldqte);         panelventes.add (labelpromo);         panelventes.add (fieldpromoeuros);         panelventes.add (fieldpromopourcent);         panelventes.add (labeltot);         panelventes.add (fieldtotal);     } } 

try out this:

public jpanelinformations() {     //jpanel panelinformation = new jpanel(); remove new instance of panel     setlayout(new gridlayout(7,1,5,5));       jlabel labelinfo = new jlabel ("information");     jlabel labelprix = new jlabel ("prix");     jlabel labeldesc = new jlabel ("description");         jlabel labelquant = new jlabel ("quantite");         jtextfield fieldprix = new jtextfield (20);      jtextarea fielddesc = new jtextarea (20, 20);      jtextfield fieldquantite = new jtextfield (20);       add(labelinfo); //remove panelinformation.     add(labelprix);//remove panelinformation.     add(fieldprix);//remove panelinformation.     add(labeldesc);//remove panelinformation.     add(fielddesc);//remove panelinformation.     add(labelquant);//remove panelinformation.     add(fieldquantite);//remove panelinformation. } 

and

public jpanelventes() {     //jpanel panelventes = new jpanel(); remove new instance of jpanel     setlayout(new gridlayout());     jlabel labelvendre = new jlabel ("vendre");     jlabel labelqte = new jlabel ("quantite");     jlabel labelpromo = new jlabel ("promotion");     jlabel labeltot = new jlabel ("total");         jtextfield fieldqte = new jtextfield (20);      jtextfield fieldpromoeuros = new jtextfield (20);      jtextfield fieldpromopourcent = new jtextfield (20);      jtextfield fieldtotal = new jtextfield (20);        add (labelvendre); //remove panelventes     add (labelqte);//remove panelventes     add (fieldqte);//remove panelventes     add (labelpromo);//remove panelventes     add (fieldpromoeuros);//remove panelventes     add (fieldpromopourcent);//remove panelventes     add (labeltot);//remove panelventes     add (fieldtotal);//remove panelventes }