I believe you are using an API that is restricted on GAE. support for File/IO operations are very limited on GAE, and when using third party libraries such as Apache Commons, not all of their features is supported. check GAE WhiteList to see what is supported.
Often you have to look for alternatives. What might be very easy in JRE, requires some tricks to get it to work on GAE. -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
