Hi; I am developing a stand-alone Java application using AWT/Swing for user interface, the calculation part is very time consuming for large data set, could take about half hour or one hour. The calculation part is the major performance concern part. I tested it on WinNT, Win98 and Win2000, the performances are more or less equivalent, when I tested it on RedHat6.1, it considerably slower, by a couple of folds. One difference I know of is the version of j2sdk, the one on RedHat6.1 is j2sdk-1.2.2...., the one on windows machine is j2sdk-1.3..... Could the j2sdk version difference cause the application to run slower ? or any other ideas ? Thanks Jian __________________________________________________ Do You Yahoo!? Try FREE Yahoo! Mail - the world's greatest free email! http://mail.yahoo.com/