JGroups ipAddress is already in magic map; please make sure that all keys are unique

Question

After using JGroups for several days without hiccups I suddenly get this error back which I'm not able to decipher. Anyone has any idea on the subject?

Caused by: java.lang.Exception: key 1 (org.jgroups.stack.IpAddress) is already in magic map; please make sure that all keys are unique
    at org.jgroups.conf.ClassConfigurator.init(ClassConfigurator.java:95)
    at org.jgroups.conf.ClassConfigurator.<clinit>(ClassConfigurator.java:60)
    ... 18 more
Exception in thread "Timer-0" java.lang.AbstractMethodError: gnu.xml.dom.DomDocument.getXmlStandalone()Z
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.setDocumentInfo(DOM2TO.java:377)
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse(DOM2TO.java:131)
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2TO.parse(DOM2TO.java:98)
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transformIdentity(TransformerImpl.java:683)
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:727)
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:340)
    at java.util.prefs.XmlSupport.writeDoc(XmlSupport.java:276)
    at java.util.prefs.XmlSupport.exportMap(XmlSupport.java:355)
    at java.util.prefs.FileSystemPreferences$7.run(FileSystemPreferences.java:622)
    at java.util.prefs.FileSystemPreferences$7.run(FileSystemPreferences.java:615)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.util.prefs.FileSystemPreferences.writeBackCache(FileSystemPreferences.java:614)
    at java.util.prefs.FileSystemPreferences.syncSpiPrivileged(FileSystemPreferences.java:801)
    at java.util.prefs.FileSystemPreferences.access$2300(FileSystemPreferences.java:50)
    at java.util.prefs.FileSystemPreferences$12.run(FileSystemPreferences.java:771)
    at java.util.prefs.FileSystemPreferences$12.run(FileSystemPreferences.java:769)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.util.prefs.FileSystemPreferences.syncSpi(FileSystemPreferences.java:768)
    at java.util.prefs.AbstractPreferences.sync2(AbstractPreferences.java:1332)
    at java.util.prefs.AbstractPreferences.sync2(AbstractPreferences.java:1337)
    at java.util.prefs.AbstractPreferences.sync2(AbstractPreferences.java:1337)
    at java.util.prefs.AbstractPreferences.sync2(AbstractPreferences.java:1337)
    at java.util.prefs.AbstractPreferences.sync(AbstractPreferences.java:1323)
    at java.util.prefs.FileSystemPreferences.sync(FileSystemPreferences.java:747)
    at java.util.prefs.FileSystemPreferences.flush(FileSystemPreferences.java:824)
    at java.util.prefs.FileSystemPreferences.syncWorld(FileSystemPreferences.java:464)
    at java.util.prefs.FileSystemPreferences.access$1200(FileSystemPreferences.java:50)
    at java.util.prefs.FileSystemPreferences$3.run(FileSystemPreferences.java:432)
    at java.util.TimerThread.mainLoop(Timer.java:555)
    at java.util.TimerThread.run(Timer.java:505)

Answer 1

Ok, found that the library gnujaxp.jar messes with JGroups. Hope this can help someone getting this strange error. I don't know if it can be considered a bug in JGroups though.