Configuration like this causes an exception (empty username value):

<subsystem xmlns="urn:jboss:domain:osgi:1.0" activation="eager">
  <configuration pid="org.apache.felix.webconsole.internal.servlet.OsgiManager">
    <property name="manager.root">jboss-osgi</property>
    <property name="username"></property>
  </configuration>

It would be useful to fix this since the Felix Web Console uses an empty username to mean: no authentication ( http://felix.apache.org/site/apache-felix-web-console.html )

This is the exception:
11:33:00,020 ERROR [stderr] Exception in thread "Controller Boot Thread" java.lang.RuntimeException: org.jboss.as.controller.persistence.ConfigurationPersistenceException: Failed to parse configuration
11:33:00,020 ERROR [stderr] at org.jboss.as.controller.AbstractControllerService$1.run(AbstractControllerService.java:89)
11:33:00,020 ERROR [stderr] at java.lang.Thread.run(Thread.java:680)
11:33:00,020 ERROR [stderr] Caused by: org.jboss.as.controller.persistence.ConfigurationPersistenceException: Failed to parse configuration
11:33:00,020 ERROR [stderr] at org.jboss.as.controller.persistence.XmlConfigurationPersister.load(XmlConfigurationPersister.java:115)
11:33:00,021 ERROR [stderr] at org.jboss.as.controller.AbstractControllerService.boot(AbstractControllerService.java:104)
11:33:00,021 ERROR [stderr] at org.jboss.as.server.ServerService.boot(ServerService.java:193)
11:33:00,021 ERROR [stderr] at org.jboss.as.controller.AbstractControllerService$1.run(AbstractControllerService.java:83)
11:33:00,021 ERROR [stderr] ... 1 more
11:33:00,021 ERROR [stderr] Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[166,43]
11:33:00,021 ERROR [stderr] Message: Value for property username is null
11:33:00,022 ERROR [stderr] at org.jboss.as.osgi.parser.OSGiExtension$OSGiSubsystemParser.parseConfigurationElement(OSGiExtension.java:225)
11:33:00,022 ERROR [stderr] at org.jboss.as.osgi.parser.OSGiExtension$OSGiSubsystemParser.readElement(OSGiExtension.java:112)
11:33:00,022 ERROR [stderr] at org.jboss.as.osgi.parser.OSGiExtension$OSGiSubsystemParser.readElement(OSGiExtension.java:94)
11:33:00,022 ERROR [stderr] at org.jboss.staxmapper.XMLMapperImpl.processNested(XMLMapperImpl.java:100)
11:33:00,022 ERROR [stderr] at org.jboss.staxmapper.XMLExtendedStreamReaderImpl.handleAny(XMLExtendedStreamReaderImpl.java:69)
11:33:00,022 ERROR [stderr] at org.jboss.as.controller.parsing.StandaloneXml.parseServerProfile(StandaloneXml.java:311)
11:33:00,023 ERROR [stderr] at org.jboss.as.controller.parsing.StandaloneXml.readServerElement(StandaloneXml.java:163)
11:33:00,023 ERROR [stderr] at org.jboss.as.controller.parsing.StandaloneXml.readElement(StandaloneXml.java:91)
11:33:00,023 ERROR [stderr] at org.jboss.as.controller.parsing.StandaloneXml.readElement(StandaloneXml.java:79)
11:33:00,023 ERROR [stderr] at org.jboss.staxmapper.XMLMapperImpl.processNested(XMLMapperImpl.java:100)
11:33:00,023 ERROR [stderr] at org.jboss.staxmapper.XMLMapperImpl.parseDocument(XMLMapperImpl.java:59)
11:33:00,023 ERROR [stderr] at org.jboss.as.controller.persistence.XmlConfigurationPersister.load(XmlConfigurationPersister.java:107)
11:33:00,024 ERROR [stderr] ... 4 more