title: Java JScrollBar not scrolling all the way
body: <p>So I have asked a previous question and this is a follow up to it, and I think it deserves its own question. I have this code where a JPanel of a certain size exists in a JScrollPane. The thing is, I want to set my own maximum values to the scroll bars of the JScrollPane which is easy using the <code>bar.setMaximum(value)</code> method. However, there is a weird problem occurring when I scroll the bars <em>without using my mouse itself but rather with the W, A, S, D</em> keys.</p>
  <p>The problem is that I set the scroll bars to new maximums, and make a change listener to update the maximums of the scroll bars (because if you looked at my previous question, the scroll bars values were returning to their default max sizes and not the ones I set them to). I thought I solved the problem to the previous question, but now the scroll bars won't scroll all the way, and stop at a certain point. Any ways to fix this?</p>
  <p><strong>Note: I don't want to change the JPanel's size that exists in the scroll pane, I just want making the scrolling longer when going from side to side with the W, A, S, D keys. (My unit increment is 1 which is too large for me, so changing the max size of the scroll bars seemed fit as that would decrease an increment’s size overall)</strong></p>
  <p>Here is the minimal reproducible (I drew a rectangle in the JPanel <code>map</code> to help see what's going on):</p>
  <pre><code>
  import javax.swing.*;
  import javax.swing.event.ChangeEvent;
  import javax.swing.event.ChangeListener;
  
  import java.awt.event.*;
  import java.awt.*;
  
  public class Test implements KeyListener, ChangeListener {
             private static JScrollPane view;   
  
             public Test() { 
                 create();
             }
  
             public static void main(String[] args) {
                 new Test();
             }
  
             public void create() {
                JFrame frame = new JFrame(); //make frame
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setSize(1000, 1000);
                frame.setLocationRelativeTo(null);
                frame.setResizable(false);
  
                SpringLayout layout = new SpringLayout(); 
                JPanel base = new JPanel();
                base.setPreferredSize(new Dimension(1000, 1000));
                base.setLayout(layout);
                  
                JPanel map = new JPanel() {
                  public void paint(Graphics g) {
                      super.paint(g);
                      g.drawRect(0, 0, 995, 100);
                  }
                };
                map.setPreferredSize(new Dimension(1000, 1000));
                
                
                view = new JScrollPane(map);
                
                view.setFocusable(true);
                view.addKeyListener(this);
                view.setPreferredSize(new Dimension(300, 300));
                layout.putConstraint(SpringLayout.HORIZONTAL_CENTER, view, 0, SpringLayout.HORIZONTAL_CENTER, base);
                layout.putConstraint(SpringLayout.VERTICAL_CENTER, view, 0,  SpringLayout.VERTICAL_CENTER, base);
                base.add(view); //add scrollpane to base jpanel
  
                frame.add(base);
                frame.setVisible(true);
                
                JScrollBar hBar = view.getHorizontalScrollBar();
                JScrollBar vBar = view.getVerticalScrollBar();
                
                hBar.getModel().addChangeListener(this);
                vBar.getModel().addChangeListener(this);
                
                hBar.getModel().setMaximum(10*800); 
                vBar.getModel().setMaximum(10*800);
             }
  
             public void stateChanged(ChangeEvent event) { //change max whenever model's max tries to default
                   BoundedRangeModel model = (BoundedRangeModel) event.getSource();
                   model.setMaximum(10*800);
               }
             
             public void keyPressed(KeyEvent event) {  //W, A, S, D keys to change values of jscrollbars
                 int verticalValue = view.getVerticalScrollBar().getModel().getValue();
                  int horizontalValue = view.getHorizontalScrollBar().getModel().getValue();
                  
                  switch (event.getKeyCode()) {
                  case KeyEvent.VK_W:
                      view.getVerticalScrollBar().getModel().setValue(verticalValue - 10);
                      break;
                  case KeyEvent.VK_S:
                      view.getVerticalScrollBar().getModel().setValue(verticalValue + 10);
                      break;
                  case KeyEvent.VK_A:
                      view.getHorizontalScrollBar().getModel().setValue(horizontalValue - 10);
                      break;
                  case KeyEvent.VK_D:
                      view.getHorizontalScrollBar().getModel().setValue(horizontalValue + 10);
                      break;
                  }
             }
  
          @Override
          public void keyTyped(KeyEvent e) {
              // TODO Auto-generated method stub
              
          }
  
          @Override
          public void keyReleased(KeyEvent e) {
              // TODO Auto-generated method stub
              
          }
  }
  </code></pre>