java - MultipartServletWebRequest.getFiles() returns empty map -

in wicket 1.5 processed uploaded files in way:

public uploadvaluepage(pageparameters parameters) {     super(parameters);     bytes maxsize = bytes.kilobytes(20000);     servletwebrequest swr = (servletwebrequest) getrequest();     multipartservletwebrequest mswr = swr.newmultipartwebrequest(maxsize, "uploadid");     fileitem item = mswr.getfile("fileinput").get(0);     // process item } 

but after migrating wicket 6 there no files in map. why?

after searching on web found this:
http://wicketinaction.com/2012/11/uploading-files-to-wicket-iresource/

so need line since wicket 6.18.0:

public uploadvaluepage(pageparameters parameters) {     super(parameters);     bytes maxsize = bytes.kilobytes(20000);     servletwebrequest swr = (servletwebrequest) getrequest();     multipartservletwebrequest mswr = swr.newmultipartwebrequest(maxsize, "uploadid");     mswr.parsefileparts(); // since wicket 6.18.0     fileitem item = mswr.getfile("fileinput").get(0);     // process item }