ConcurrentModificationException : TransferEventSupport needs synchronization

I get some thraead-safety issues with maven archiva :

2007-04-02 10:11:25,392 [http-8888-1] ERROR [RepositoryServlet] - "Servlet.service()" pour la servlet RepositoryServlet a généré une exception
java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
at java.util.AbstractList$Itr.next(Unknown Source)
at org.apache.maven.wagon.events.TransferEventSupport.fireTransferProgress (TransferEventSupport.java:117)
at org.apache.maven.wagon.AbstractWagon.fireTransferProgress(AbstractWagon.java:350)

There is a thread-safety issue in Wagon TransferEventSupport

The listeners list is an ArrayList and add/remove/fireEvent methods are not synchronized.
This requires either synchronization or use of a CopyOnWriteArrayList (java5 or backport).