@Override
        public void handleReply(Reply reply) {
            if (reply.getTrace().getLevel() > 0) {
                log.log(Level.INFO, reply.getTrace().toString());
            }
            OperationContext context = (OperationContext) reply.getContext();
            long reqId = context.reqId;
            Response response = reply.hasErrors() ? toError(reply, reqId) : toSuccess(reply, reqId);
            ResponseHandler operationSpecificResponseHandler = context.responseHandler;
            if (operationSpecificResponseHandler != null)
                operationSpecificResponseHandler.handleResponse(response);
            else if (handler != null) {
                handler.handleResponse(response);
            } else {
                queue.add(response);
            }
        }
Returns a concatenated error string from the errors contained in a reply.

@param reply The reply whose errors to concatenate.
@return The error string.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/MessageBusAsyncSession.java