When the uploaded file gets rejected because it's content, size, or because of a general problem an Exception is thrown by the MultiPartRequest class. Exceptions are: InvalidContentTypeException, UnknownSizeException, SizeLimitExceededException, and FileUploadException. This can lead to serious problems within the application because the other parameters from the upload form get lost. Happening in a profile page for example means that the user data is lost this can lead to a security Exception. In other case this usually just involves a OGNL-Exception. Meaning your field data like personal file name is lost. Workaround found in http://henning.kropponline.de/index.php/2009/01/18/struts2-fileuploadbase-exception/, but the the still keep uploading to server, not secured.