this issue only occurs when deployed within an IDE to an application server that uses it's own way to deploy (in other words, the files are not physically in the /webapps (for tomcat) folder of the application server). Intellij and Eclipse do this when you use the IDE to deploy an application -> non-filesystem deployment
What happens is that CoreUtils.getRealPath(facesContext, FILE_SEPARATOR); returns null and so the folder to upload to becomes "null uploads/.........." etc.
When physically deploying the application to the server, the uploads directory path is correct for example.....:-
INFO: abs file=/Users/jguglielmin/icefaces/servers/apache-tomcat-7.0.23/webapps/mobitest/uploads/433CE8CB7B8AAD97342586FD2CAB1572/bebeea8f-cbea-4494-97e3-1bf1381f97e6.jpg

when deployed within the IDE you can replace the uploads to "/nulluploads/" and then you can't find the file to show it afterwards.