The JFileChooser return a null value when user select a nonexist file in the fold (by just typing it in the text file of pop up window, then click open or save button). It return that file name in previous JRE release, 1.4.2 and 1.3, and I think it even works in early tiger build. This caused a big problem when we try to export a certficate into a file, if that file isn't exist in the directory, the operation will fail.

I have attached a testcase to approve it. Please try to run it in early JRE release, it works fine.