Problem visualizing a JFrame while doing other things

Question

I'm triing to visualize a "Waiting" Window with static labels on it saying "Wait please, this process can take some time..." while doing something like 20000 insert in a database, but the window shows only at the end of the process (when i have to open another window, so it displays for only a millisecond). How can i solve the problem? Code is like this:
public class myclass extends JFrame {
// some dichiaration
public myclass() {
try{
jbinit()
} catch ...
// do alot of calculation
private void jbinit() {
// all the stuff like setsize and labels definition
}

Answer 1

You're probably doing the entire work in the Swing thread and block it from doing anything else.
http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html