The issue is caused by the call to javax.servlet.http.Part.write(fileName) which should save the uploaded content but the provided file path is absolute instead of relative as it is required (see https://docs.oracle.com/javaee/6/api/javax/servlet/http/Part.html#write(java.lang.String) ).

Modified PartFile.transferFile method to just use a FileOutputStream instead (just as we already do in ICEfaces4).

Testing EE-3.3.0-maintenance branch r. 47018 using the test case passes on Jetty 9.2.9, IE11, FF41, Chrome47.

Testing showcase > fileEntry on EE-3.3.0-maintenance branch r. 47018/ IF4 trunk r. 47018 fails on Jetty 9.2.9, all browsers (no issues on Tomcat7).
ICEfaces EE-3.3.0-maintenance branch r47018/all browsers:
On all demos, files are not uploaded on the server. There are no server/browser console errors.

ICEfaces4 trunk 4 r47018/ all browsers:
Files are uploaded on all demos; however server errors occur when clicking the "+" icon to view the Source Code from the fileEntry demos.

2016-01-25 10:57:00.207:WARN:oejs.ServletHandler:qtp360203475-16: /showcase/sourcecodeStream.html
java.lang.NullPointerException
at java.io.File.<init>(File.java:277)
at org.icefaces.samples.showcase.util.SourceCodeLoaderServlet.getSource(SourceCodeLoaderServlet.java:76)
at org.icefaces.samples.showcase.util.SourceCodeLoaderServlet.doGet(SourceCodeLoaderServlet.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:808)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:587)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:110)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
at org.eclipse.jetty.server.Server.handle(Server.java:497)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:310)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
at java.lang.Thread.run(Thread.java:744)
java.io.IOException: Server returned HTTP response code: 500 for URL: http://localhost:8080/showcase/sourcecodeStream.html?path=%2FWEB-INF%2Fclasses%2Forg%2Fice
faces%2Fsamples%2Fshowcase%2Fexample%2Face%2Ffileentry%2FFileEntryBean.java
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1626)
at java.net.URLConnection.getContent(URLConnection.java:748)
at java.net.URL.getContent(URL.java:1051)
at org.icefaces.samples.showcase.util.SourceCodeLoaderConnection.get(SourceCodeLoaderConnection.java:155)
at org.icefaces.samples.showcase.util.SourceCodeLoaderConnection.get(SourceCodeLoaderConnection.java:40)
at javax.el.MapELResolver.getValue(MapELResolver.java:65)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
............

Testing EE 3.3.0 code on Jetty shows that the files are saved. The only quirk is that Jetty cannot calculate the folder name for where the files are to be saved, instead it will use the {app}/null/{session id} pattern.

Applied a fix to EE 3.3.0 CoreUtils.getRealPath to return a null reference when the real path cannot be calculated thus ensuring that the FileEntry will fallback to use the web application root as location for saving the files.

Renamed org.icefaces.samples.showcase.example.ace.file package to org.icefaces.samples.showcase.example.ace.fileentry to conform to the conventions used by showcase application for locating the source files. The commit is fixing the issue found in IF4 that occurs in Jetty and Tomcat.

About the EE-3.3.0-maintenance testing, the web.xml in showcase needs to be modified to enable the Servlet 3 functionality. So <multipart-config> and <web-app version="3.0" .../> tags need to be uncommented. By doing so the file upload will run properly on Jetty.

Thanks, Mircea.
Verified showcase > fileEntry and Arran's test case on Jetty 9.2.9 with ICEfaces4 trunk r. 47032/ EE-3.3.0-maintenance r.47032 on IE8, IE11, FF41, Chrome47.
No errors or file upload issues found.

Verified showcase > fileEntry demos from ICEfaces 4.1.1. Jenkins Build #2 on Chrome48, IE11.