Program: 51445
Project: 51445
Buggy source:
@Override public void startElement(Element element){
  if (element instanceof JourneyHeaderElement) {
    JourneyHeaderElement journey=(JourneyHeaderElement)element;
    AgencyAndId journeyId=new AgencyAndId(journey.getOperatorId(),journey.getJourneyIdentifier());
    List<JourneyHeaderElement> journies=_journeysById.get(journeyId);
    if (journies == null) {
      journies=new ArrayList<JourneyHeaderElement>();
      _journeysById.put(journeyId,journies);
    }
    journies.add(journey);
    AgencyAndId routeId=getRouteIdForJourney(journey);
    RouteMetadata metadata=getMetadataForRouteId(routeId);
    metadata.addDirection(journey.getRouteDirection());
  }
 else   if (element instanceof LocationElement) {
    LocationElement location=(LocationElement)element;
    _locationById.put(location.getLocationId(),location);
  }
 else   if (element instanceof AdditionalLocationElement) {
    AdditionalLocationElement location=(AdditionalLocationElement)element;
    _additionalLocationById.put(location.getLocationId(),location);
  }
 else   if (element instanceof VehicleTypeElement) {
    VehicleTypeElement vehicle=(VehicleTypeElement)element;
    _vehicleTypesById.put(vehicle.getId(),vehicle);
  }
 else   if (element instanceof RouteDescriptionElement) {
    RouteDescriptionElement route=(RouteDescriptionElement)element;
    AgencyAndId id=new AgencyAndId(route.getOperatorId(),route.getRouteNumber());
    RouteMetadata metadata=getMetadataForRouteId(id);
    metadata.addRouteDescription(route);
  }
 else   if (element instanceof OperatorElement) {
    OperatorElement operator=(OperatorElement)element;
    OperatorElement existing=_operatorsById.put(operator.getOperatorId(),operator);
    if (existing != null) {
      _log.info("String_Node_Str");
    }
  }
 else   if (element instanceof NationalExpressLocationNameElement) {
    NationalExpressLocationNameElement nxNameElement=(NationalExpressLocationNameElement)element;
    _nxLocationNamesById.put(nxNameElement.getLocationId(),nxNameElement);
  }
}

Fixed version (ground truth):
@Override public void startElement(Element element){
  if (element instanceof JourneyHeaderElement) {
    JourneyHeaderElement journey=(JourneyHeaderElement)element;
    AgencyAndId journeyId=new AgencyAndId(journey.getOperatorId(),journey.getJourneyIdentifier());
    List<JourneyHeaderElement> journies=_journeysById.get(journeyId);
    if (journies == null) {
      journies=new ArrayList<JourneyHeaderElement>();
      _journeysById.put(journeyId,journies);
    }
    journies.add(journey);
    AgencyAndId routeId=getRouteIdForJourney(journey);
    RouteMetadata metadata=getMetadataForRouteId(routeId);
    metadata.addDirection(journey.getRouteDirection());
  }
 else   if (element instanceof LocationElement) {
    LocationElement location=(LocationElement)element;
    _locationById.put(location.getLocationId(),location);
  }
 else   if (element instanceof AdditionalLocationElement) {
    AdditionalLocationElement location=(AdditionalLocationElement)element;
    _additionalLocationById.put(location.getLocationId(),location);
  }
 else   if (element instanceof VehicleTypeElement) {
    VehicleTypeElement vehicle=(VehicleTypeElement)element;
    _vehicleTypesById.put(vehicle.getId(),vehicle);
  }
 else   if (element instanceof RouteDescriptionElement) {
    RouteDescriptionElement route=(RouteDescriptionElement)element;
    AgencyAndId id=new AgencyAndId(route.getOperatorId(),route.getOperatorId() + "String_Node_Str" + route.getRouteNumber());
    RouteMetadata metadata=getMetadataForRouteId(id);
    metadata.addRouteDescription(route);
  }
 else   if (element instanceof OperatorElement) {
    OperatorElement operator=(OperatorElement)element;
    OperatorElement existing=_operatorsById.put(operator.getOperatorId(),operator);
    if (existing != null) {
      _log.info("String_Node_Str");
    }
  }
 else   if (element instanceof NationalExpressLocationNameElement) {
    NationalExpressLocationNameElement nxNameElement=(NationalExpressLocationNameElement)element;
    _nxLocationNamesById.put(nxNameElement.getLocationId(),nxNameElement);
  }
}