There are several ways to run XWiki on Jetty:

• Using the Demo packaging (a.k.a Standalone packaging) which bundles Jetty and provide an all-in-one zip, ready to use.
• Using the official Jetty docker image.
• Downloading and instaling Jetty manually on your server.

If you go with the last 2 options, make sure to:

• Pick a supported version of Jetty.
• Follow the Jetty setup defined in the xwiki.mod file used for the demo packaging. Note that the default setup used in the Jetty Docker image should work fine out of the box.
• If you're deploying XWiki on a Jetty 10+, you'll need to edit the WEB-INF/jetty-web.xml file since it currently contains a setup valid for Jetty 9.x and it'll fail in Jetty 10+. You'll need to remove the calls to prependSystemClass and prependServerClass. For example (best is to edit your version so that you can get the latest changes in it):
  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE Configure PUBLIC "-//Jetty//Configure//EN" "https://www.eclipse.org/jetty/configure_9_0.dtd">
  <Configure class="org.eclipse.jetty.webapp.WebAppContext">
   <Set name="maxFormContentSize">1000000</Set>
   <Set name="maxFormKeys">2000</Set>
  </Configure>

Docker

• Extract the XWiki WAR into a directory named xwiki. Let's call this directory [XWIKI_HOME].
• Run the Jetty Docker image, for example: docker run -v [XWIKI_HOME]:/var/lib/jetty/webapps/xwiki -p 8080:8080 jetty:9-jre11

Manual

• Download and install Jetty. It's usually as simple as unzipping it in a directory. Let's call this directory [JETTY_HOME].
• Extract the XWiki WAR into a directory named xwiki in [JETTY_HOME]/webapps/.
• Open [JETTY_HOME]/webapps/xwiki/WEB-INF/xwiki.properties files and configure a permanent directory
• (Optional) If you want to modify the port on which Jetty will run, edit [JETTY_HOME]/start.ini. Search for 8080, replace it with the port value you wish to use and uncomment the corresponding property jetty.http.port.

Troubleshooting

Unable to parse form content

In some cases you could obtain one of the following error messages: Unable to parse form content.

More specifically: org.eclipse.jetty.http.BadMessageException: 400: Unable to parse form content.

This can be related to a form containing too many parameters. In order to fix this issue, you can modify your jetty.xml file as explained in Configuring form limits for the server.