ConcurrentModificationException in AbstractRuleBase.removePackage

At AbstractRuleBase.removePackage:

//and now the rule flows
final Map flows = pkg.getRuleFlows();
for (final Iterator iter = flows.keySet().iterator(); iter.hasNext();) {
     removeProcess( (String) iter.next() );
}

At AbstractRuleBase.removeProcess

this.pkgs.get(process.getPackageName()).removeRuleFlow(id);

removeProcess removes an object from the Map referenced by the flows variable in removePackage. Since the iterator is based on this variable it leads to a ConcurrentModificationException at iter.next().