Remove panel from frame

Question

CONTINUATION OF 1St MAIL
public JScrollPane ThumbnailGui(Vector vSeriesNo,Vector[] vImageNo,Vector[] LoadedFilenames)
          this.parent=parent;
          this.vSeriesNo=vSeriesNo;
          this.vImageNo=vImageNo;
          this.LoadedFilenames=LoadedFilenames;
               try{
          MainPanel=new JPanel();
          MainPanel.setLayout(new BoxLayout(MainPanel,BoxLayout.Y_AXIS));
          LineBorder lineborder=new LineBorder(Color.red,2,true);
          MainPanel.setBorder(lineborder);     
          int LoadedFilenamesSize=LoadedFilenames[0].size();
          int LoadedSeriesSize=vSeriesNo.size();
          System.out.println("*******Im under Thumbnial GUI");
          Thumbnail=new JButton[LoadedSeriesSize][LoadedFilenamesSize];     
          for(int count=0;count<1;count++)
               System.out.println("Vector creation");
               vImageNo1[count]=new Vector();
               LoadedFilenames1[count]=new Vector();
               for(int j=0;j<vSeriesNo.size();j++)
                    for(int i=0;i<vImageNo[j].size();i++)
                         str=LoadedFilenames[j].elementAt(i).toString().replace('~','\\');
                         str=str.replace(".dcm",".jpg");
                         Icon ic=new ImageIcon(str);
                         Thumbnail[j]=new JButton(ic);
                         Thumbnail[j][i].addActionListener(new ThumbnailAction());
                         MainPanel.add(Thumbnail[j][i]);
                    }//inner for
               }//outer for
                                   //     MainPanel.setVisible(true);
               heightScrollbar = new JScrollPane(MainPanel);
          heightScrollbar.setName("height");
               heightScrollbar.setVisible(true);
               MainPanel.updateUI();
               heightScrollbar.updateUI();          
          }catch(Exception e){
               e.printStackTrace();
               return heightScrollbar;
     }//ThumbnailGui()
     public void removePanel()
     public void loadimage()
class ThumbnailAction implements ActionListener
          public void actionPerformed(ActionEvent ae)
               JButton ThumbnailEvent =(JButton)ae.getSource();          
               String Series="",Imageno="",FilePath="";
               vSeriesNo1.removeAllElements();                    
               for(int count=0;count<1;count++)
               vImageNo1[count].removeAllElements();
               LoadedFilenames1[count].removeAllElements();
                              System.out.println("*******Im under Thumbnial Action Listener");
          for(int j=0;j<vSeriesNo.size();j++)
                    for(int i=0;i<vImageNo[j].size();i++)
                         if(ThumbnailEvent==Thumbnail[j][i])
                                             //Properties dicomheaderdetails = (Properties)parent.htHeaderData.get(vSeriesNo.elementAt(j)+"+"+i);
                                        try
                                                  FilePath=LoadedFilenames[j].elementAt(i).toString().replace('~','\\');
                                                  System.out.println("File name is :"+FilePath);
                                                  Imageno = vImageNo[j].elementAt(i).toString();
                                                  System.out.println("Thumbnail Image Number is : "+Imageno);                                              
                                                  Series = vSeriesNo.elementAt(j).toString();
                                                  System.out.println("Thumbnail Series Number is : "+Series);                              
                                             }catch (Exception e)
                                                       e.printStackTrace();
                    }//inner for
               }//outer for          
          vSeriesNo1.addElement(Series);
          vImageNo1[0].addElement(Imageno);
          LoadedFilenames1[0].addElement(FilePath);
          parent.imageLoader = new ImageLoader(parent,vSeriesNo1,vImageNo1,LoadedFilenames1,false,1);          
     }//class

Answer 1

If you want to add/remove components from a panel then the code should be something like:
panel.add( something );
panel.revalidate();
panel.repaint();
If you want to replace an entire panel then you should probably be using a [Card Layout|http://java.sun.com/docs/books/tutorial/uiswing/layout/card.html].