SWING GUI blockes when doing a DB action with microsoft nativ JDBC driver

Question

hi,
in a bigger project i have the problem that if i perform a DB action the GUI is blocked. It does not matter if i do the DB Action in invokeLater or
in a SwingWorker or in a new Thread if i call the DB Action and i move another window over my window it is not refreshed.
normally the GUI shouln�t be blocked if i use invokeLater. maybe it
has something to do that i use the native DB driver? I am using JDK
1.4. has anyone ever encounterd the same problem?
alex
package swingtest;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
public class GUIProblem extends JDialog {   
// this method does a simple DB call to generate some load
public void doMyDBCall()
try {
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
Connection con = DriverManager.getConnection ("jdbc:microsoft:sqlserver://abgvdr71:1433;databasename=v52li;","sa","");
Statement question0 = con.createStatement();
ResultSet rs0=null;
rs0 = question0.executeQuery("select * from intercept_24");
boolean more=rs0.next();
while (more) {    more=rs0.next();}
catch (Exception sql)
{ sql.printStackTrace(); }
public void doItinvokeLater()
SwingUtilities.invokeLater(new Runnable(){    public void run(){       
doMyDBCall();     
public void doItSwingWorker()
SwingWorker worker = new SwingWorker() {
public Object construct() {
System.out.println("worker start");
doMyDBCall();
return null;
worker.start();
System.out.println("finished .....");
Object view = (Object) worker.get();
public GUIProblem (){
super((JFrame)null,"",true);
JButton button = new JButton("do it");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event)
// calls it direct -> GUI blocked
//doMyDBCall();
// with invoke later -> GUI blocked
//doItinvokeLater();
// with the swingWorker -> GUI also blocks
doItSwingWorker();     
getContentPane().add(button);
setSize(200,200);
setVisible(true);
public static void main(String [] args)
{  new GUIProblem(); }
}

Answer 1

The invokeLater runs the Runnable in the event thread, so yes, that will block your GUI. You ALMOST got the SwingWorker right. DB call in the construct() method -- the construct() method executes outside the event thread, the finished() method executes in the event thread. The only problem is, you did a worker.get() method in your event thread (right after worker.start(0, and get() blocks until result is ready from construct() -- so, bingo, you're jammed up waiting in you event thread.