JSF2 on Jetty gives randomly 'zip file closed'

The following was posted on stackoverflow: http://stackoverflow.com/questions/7715985/jsf2-on-jetty-gives-randomly-zip-file-closed-but-works-when-running-from-maven

I am experiencing the same issue. Seemingly randomly, resources aren't sent to the client and I get these exceptions in the log:

java.lang.IllegalStateException: zip file closed
at java.util.zip.ZipFile.ensureOpen(ZipFile.java:416)
at java.util.zip.ZipFile.access$100(ZipFile.java:31)
at java.util.zip.ZipFile$2.hasMoreElements(ZipFile.java:316)
at java.util.jar.JarFile$1.hasMoreElements(JarFile.java:222)
at org.eclipse.jetty.util.resource.JarFileResource.exists(JarFileResource.java:163)
at org.eclipse.jetty.webapp.WebAppContext.getResource(WebAppContext.java:321)
at org.eclipse.jetty.webapp.WebAppContext$Context.getResource(WebAppContext.java:1222)
at org.eclipse.jetty.servlet.DefaultServlet.getResource(DefaultServlet.java:366)
at org.eclipse.jetty.server.ResourceCache.lookup(ResourceCache.java:188)
at org.eclipse.jetty.servlet.DefaultServlet.doGet(DefaultServlet.java:445)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:547)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1359)

I haven't been able to get the workaround mentioned in the post working, but I have found similar threads on other sites claiming the same workaround works.