Panels resizable contained in a frame resizable

Question

Hello to all,
I have the following question, how is it possible to make resizable the panels contained in the frame when frame's resized by the user?
I had already a look at the swing tutorial but I didn't find the solution :( (may be I didn't understand )
Can anybody help me?
I attach here bellow my code
Thansk in advance
Mandy
ublic class SecondClass  extends JFrame{     
     JTextArea cfgArea;
     JTextArea relArea;
     JTextArea resultArea;
     JComboBox searchModeCB;
     public SecondClass(){
         JFrame frame = new JFrame("title");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setResizable(true);
         JPanel mainPanel = new JPanel();
         mainPanel.setBackground(Color.cyan);
         mainPanel.setSize(600,400);
         mainPanel.setLayout(null);
         JPanel  cfgPane = new JPanel ();
         cfgPane.setLayout(null);
         cfgPane.setBackground(Color.red);
         cfgPane.setBounds(10,10,370,280);
         mainPanel.add(cfgPane);
         cfgArea = new JTextArea();
         cfgArea.setBorder(BorderFactory.createEtchedBorder());
         cfgArea.setDragEnabled(true);
         cfgArea.setTransferHandler(new CustomedTransferHandler());
         cfgArea.setDropMode(DropMode.INSERT);
         JScrollPane cfgScrollPane = new JScrollPane(cfgArea);
         cfgScrollPane.setBounds(10, 20, 350, 200);
         cfgPane.add(cfgScrollPane);
         JButton clearCfgButton = new JButton("Clear");
         clearCfgButton.setBounds(70, 230, 70, 20);
         cfgPane.add(clearCfgButton);
         JButton addCfgButton = new JButton("Add");
         addCfgButton.setBounds(200, 230, 60, 20);
         cfgPane.add(addCfgButton);
         mainPanel.add(cfgPane);
         JPanel relPane =  new JPanel();
         relPane.setLayout(null);
         relPane.setBackground(Color.blue);
         relPane.setBounds(10,300,370,280);
         mainPanel.add(relPane);
         relArea = new JTextArea();
         relArea.setBorder(BorderFactory.createEtchedBorder());
         relArea.setDragEnabled(true);
         relArea.setTransferHandler(new CustomedTransferHandler());
         relArea.setDropMode(DropMode.INSERT);
         JScrollPane relScrollPane = new JScrollPane(relArea);
         relScrollPane.setBounds(10, 20, 350, 200);
         relPane.add(relScrollPane);
         JButton clearRelButton = new JButton("Clear");
         clearRelButton.setBounds(20, 230, 70, 20);
         relPane.add(clearRelButton);
         JButton addRelButton = new JButton("Add");
         addRelButton.setBounds(110, 230, 60, 20);
         relPane.add(addRelButton);
         String[] items = {"Something"};
         searchModeCB = new JComboBox(items);
         searchModeCB.setBounds(180, 230, 180, 20);
         searchModeCB.setSelectedItem("Something");
         relPane.add(searchModeCB);
         JButton okRelButton = new JButton("Ok");
         okRelButton.setBounds(300, 255, 60, 20);
         relPane.add(okRelButton);
         JPanel resultPane = new JPanel();
         resultPane.setLayout(null);
         relPane.setBackground(Color.yellow);
         resultPane.setBounds(390,10,580,570);
         resultArea = new JTextArea();
         resultArea.setBorder(BorderFactory.createEtchedBorder());
        mainPanel.add(resultPane);
         JScrollPane resultScrollPane = new JScrollPane(resultArea);
         resultScrollPane.setBounds(10, 20, 560, 490);
         resultPane.add(resultScrollPane);
         JButton clearResButton = new JButton("Clear");
         clearResButton.setBounds(120, 520, 80, 20);
         resultPane.add(clearResButton);
         JButton saveResultButton = new JButton("Save");
         saveResultButton.setBounds(380, 520, 80, 20);
         resultPane.add(saveResultButton);
         JButton exitButton = new JButton("Exit");
         exitButton.setBounds(495, 550, 80, 15);
         resultPane.add(exitButton);
         frame.add(mainPanel);
         frame.setLocation(200,200);
         int width = 980;
         int height = 650;
         frame.setSize(width, height);
         frame.setVisible(true);
     public static void main(String[] args) {
          // TODO Auto-generated method stub
          SecondClass main = new SecondClass();
}

Answer 1

ok did some modifications.
Now it works as I want
     public SecondClass(){
         JFrame frame = new JFrame("title");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setResizable(true);
         JPanel  mainPanel = new JPanel ();
         mainPanel.setSize(600,400);
         mainPanel.setLayout(new GridLayout(0,2));
         JPanel sxPanel = new JPanel();
         sxPanel.setBackground(Color.blue);
         sxPanel.setLayout(new GridLayout(2,0));
         mainPanel.add(sxPanel);
         JPanel dxPanel = new JPanel();
         dxPanel.setLayout(new BorderLayout());
         mainPanel.add(dxPanel);
         // Create cfgArea
          JPanel  cfgPane = new JPanel ();
          cfgPane.setLayout(new BorderLayout());
         sxPanel.add(cfgPane);
         cfgPane.add(new JLabel("  "),BorderLayout.NORTH);
         cfgPane.add(new JLabel("  "),BorderLayout.EAST);
         cfgPane.add(new JLabel("  "),BorderLayout.WEST);
         cfgArea = new JTextArea();
         cfgArea.setBorder(BorderFactory.createEtchedBorder());
         cfgArea.setDragEnabled(true);
         cfgArea.setTransferHandler(new CustomedTransferHandler());
         cfgArea.setDropMode(DropMode.INSERT);
         JScrollPane cfgScrollPane = new JScrollPane(cfgArea);
         cfgPane.add(cfgScrollPane,BorderLayout.CENTER);
         JPanel southCfgPanel = new JPanel();
         cfgPane.add(southCfgPanel, BorderLayout.SOUTH);
         JButton clearCfgButton = new JButton("Clear");
         southCfgPanel.add(clearCfgButton);
         JButton addCfgButton = new JButton("Add");
         southCfgPanel.add(addCfgButton);
         //end og cfg Area
         // Create relArea     
         JPanel relPane =  new JPanel();
         relPane.setLayout(new BorderLayout());
         sxPanel.add(relPane);
         relPane.add(new JLabel("  "),BorderLayout.NORTH);
         relPane.add(new JLabel("  "),BorderLayout.EAST);
         relPane.add(new JLabel("  "),BorderLayout.WEST);
         relArea = new JTextArea();
         relArea.setBorder(BorderFactory.createEtchedBorder());
         relArea.setDragEnabled(true);
         relArea.setTransferHandler(new CustomedTransferHandler());
         relArea.setDropMode(DropMode.INSERT);
         JScrollPane relScrollPane = new JScrollPane(relArea);
         relPane.add(relScrollPane,BorderLayout.CENTER);
         JPanel southRelPanel = new JPanel();
         relPane.add(southRelPanel, BorderLayout.SOUTH);
         JButton clearRelButton = new JButton("Clear");
         southRelPanel.add(clearRelButton);
         JButton addRelButton = new JButton("Add");
         southRelPanel.add(addRelButton);
         String[] items = {"Something"};
         searchModeCB = new JComboBox(items);
         searchModeCB.setSelectedItem("Something");
         southRelPanel.add(searchModeCB);
         JButton okRelButton = new JButton("Ok");
         southRelPanel.add(okRelButton);
        //RESULT PANEL
         JPanel resultPane = new JPanel();
         resultPane.setLayout(new BorderLayout());
         dxPanel.add(new JLabel("  "),BorderLayout.NORTH);
         dxPanel.add(new JLabel("  "),BorderLayout.EAST);
         dxPanel.add(new JLabel("  "),BorderLayout.WEST);
         dxPanel.add(resultPane,BorderLayout.CENTER);
         resultArea = new JTextArea();
         resultArea.setBorder(BorderFactory.createEtchedBorder());
         resultPane.add(resultArea,BorderLayout.CENTER);
         JScrollPane resultScrollPane = new JScrollPane(resultArea);
         resultPane.add(resultScrollPane);
         JPanel southPanel = new JPanel();
         resultPane.add(southPanel, BorderLayout.SOUTH);
         JButton clearResButton = new JButton("Clear");
         southPanel.add(clearResButton);
         JButton saveResultButton = new JButton("Save");
         southPanel.add(saveResultButton);
         JButton exitButton = new JButton("Exit");
         southPanel.add(exitButton);
         frame.add(mainPanel);
         frame.setLocation(200,200);
         // Show the frame
         int width = 980;
         int height = 650;
         frame.setSize(width, height);
         frame.setVisible(true);
     }