as.maps,
Nope, it's a DTD issue, like Jan pointed out.
Either a lack of DTD or the wrong DTD is the root cause.
Fix that and it will work.
Feel free to experiment in the jetty-distribution.
Edit the demo-base/webapps/test.xml
Enable the virtualHosts section (which is commented out)
Run the demo base.
[demo-base]$ java -jar ../start.jar
It works.
Now remove the DTD line and try again
[demo-base]$ java -jar ../start.jar
2013-12-01 16:59:37.267:WARN:oejx.XmlConfiguration:main: Config error at <Set name="virtualHosts">| <Array type="String">| <Item>
www.MyVirtualDomain.com</Item>| <Item>
m.MyVirtualDomain.com</Item>| <Item>*.OtherVirtualDomain.com</Item>| <Item>@ConnectorName</Item>| <Item>localhost</Item>| <Item>127.0.0.1</Item>| </Array>| </Set> java.lang.ClassCastException: java.lang.String cannot be cast to org.eclipse.jetty.xml.XmlParser$Node in file:/home/joakim/code/intalio/distros/jetty-distribution-9.1.0.v20131115/demo-base/webapps/test.xml
2013-12-01 16:59:37.267:WARN:oejd.DeploymentManager:main: Unable to reach node goal: started
java.lang.ClassCastException: java.lang.String cannot be cast to org.eclipse.jetty.xml.XmlParser$Node
at org.eclipse.jetty.xml.XmlConfiguration$JettyXmlConfiguration.newArray(XmlConfiguration.java:872)