[I once had a similar problem, when I wanted to display a large table of
65536 characters (16 columns, 4096 rows) in a scrollpane.]

Don't use 2 scrollpanes. Use only 1 scrollpane, and set a 1-column-table
 as the row-header of the scrollpane. Assure that both tables have the
same row height. Then the scrollpane kindly keeps your 2 tables in sync.
You do the setup roughly like this:

  JTable mainTable = new JTable(...); // table with k columns, n rows,
  JTable rowHeader = new JTable(...); // table with 1 column, n rows
  // You'll probably need 2 different table models, one for each table

  JScrollPane scrollPane = new JScrollPane(mainTable);
  scrollPane.setRowHeaderView(rowHeader);

  scrollPane.setHorizontalScrollbarPolicy(...);
  scrollPane.setVerticalScrollbarPolicy(...);
  // and because you want the horizontal scrollbar:
  mainTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);

You did not mention what objects are in the scroll panes.

I found this out in the newsgroups:

"I think you may have to add a ChangeListener to the viewports of each
table. When the user scrolls in either table the ChangeListener will be
notified. Call getViewRect() to get the visible rectangle for the
viewport that has just been scrolled. Call scrollRectToVisible() on the
other viewport to synchronize"

Thanks in Advance...
IchBin, Pocono Lake, Pa, USA
http://weconsultants.servebeer.com/JHackerAppManager
__________________________________________________________________________

'If there is one, Knowledge is the "Fountain of Youth"'
-William E. Taylor,  Regular Guy (1952-)

For horizontal, just set the respective policies.
For vertical scrolling in synch, set the scrollbar models the same
simple demo:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class Testing extends JFrame
{
 public Testing()
 {
   JScrollPane sp1 = new JScrollPane(new ScrollPanel());
   JScrollBar sBar1 = sp1.getVerticalScrollBar();
   JScrollPane sp2 = new JScrollPane(new ScrollPanel());
   JScrollBar sBar2 = sp2.getVerticalScrollBar();
   sBar2.setModel(sBar1.getModel()); //<--------------synchronize
   getContentPane().setLayout(new GridLayout(1,2));
   getContentPane().add(sp1);
   getContentPane().add(sp2);
   setDefaultCloseOperation(EXIT_ON_CLOSE);
   setSize(400,300);
   setLocation(400,300);
 }
 public static void main(String[] args) {new Testing().setVisible(true);}
}
class ScrollPanel extends JPanel
{
 public ScrollPanel()
 {
   setLayout(new GridLayout(50,1));
   for(int x = 0; x < 50; x++) add(new JLabel(""+(x+1)));
 }
}