Forced Window.alert() when error occurs

[lbono]

If an exception occurs during upload operations the client always triggers a Window.alert() which cannot be avoided. When developing an application, all messages returned to users are usually consistent with the overall look&feel, so if I'm handling an exception I'd rather use my own modal popup instead of the forced Window.alert(), also giving me the chance to provide a message of my choice instead of a Java exception message.

This is the code I am referring to: https://github.com/manolo/gwtupload/blob/master/core/src/main/java/gwtupload/client/BaseUploadStatus.java#L192