title: JScrollPane not working in null layout
body: <pre><code>  import javax.swing.JCheckBox;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JPanel;
    import javax.swing.JScrollPane;
  
  public class ScrollJPanelDemo extends JFrame {
     public ScrollJPanelDemo(){
      setSize(480, 200);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  
      JLabel label = new JLabel("Select one or more options : ");
      JCheckBox jcb1 = new JCheckBox("Chandigarh");
      JCheckBox jcb2 = new JCheckBox("Mohali");
      JCheckBox jcb3 = new JCheckBox("Delhi");
      JCheckBox jcb4 = new JCheckBox("Noida");
      JCheckBox jcb5 = new JCheckBox("Mumbai");
      JCheckBox jcb6 = new JCheckBox("Kolkata");
  
      //creating JPanel to hold the checkboxes
      JPanel jpnl = new JPanel();
      jpnl.setLayout(null);
      jpnl.setOpaque(true);
      jcb1.setBounds(0,0,100,40);
              jcb2.setBounds(0,60,100,40);
              jcb3.setBounds(0,120,100,40);
              jcb4.setBounds(0,180,100,40);
              jcb5.setBounds(0,240,100,40);
              jcb6.setBounds(0,300,100,40);
      //adding check boxes and label to the JPanel
      jpnl.add(label);
      jpnl.add(jcb1);
      jpnl.add(jcb2);
      jpnl.add(jcb3);
      jpnl.add(jcb4);
      jpnl.add(jcb5);
      jpnl.add(jcb6);
  
      //creating the scroll pane that will scroll the panel.
      JScrollPane jscrlPane = new JScrollPane(jpnl);
      jscrlPane.setBounds(0,0,300,300);
  
  
  
          jscrlPane.setHorizontalScrollBarPolicy
         (JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS) ;
     jscrlPane.setVerticalScrollBarPolicy
     (JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
  
      //adding that scroll pane to the frame.
      getContentPane().add(jscrlPane);
      setVisible(true);
    }
  
      public static void main(String args[]){
              new ScrollJPanelDemo();             
          }
  
   }
  </code></pre>
  
  <p>I'm new in Java Swing and try to use of Scroll pane on my Java code, but it's not working. The Scroll Pane is add on the frame in vertical direction but not worked.</p>