// update
                        writer.write(item.toLineString());
                        writer.write(Constants.LINE_SEPARATOR);
                        return new CharMappingItem(item.getId(), item.getNewInputs(), item.getNewOutput());
                    }
                    return null;
                } finally {
                    item.setNewInputs(null);
                    item.setNewOutput(null);

                        // update
                        writer.write(item.toLineString());
                        writer.write(Constants.LINE_SEPARATOR);
                        return new SynonymItem(item.getId(), item.getNewInputs(), item.getNewOutputs());
                    }
                    return null;
                } finally {
                    item.setNewInputs(null);
                    item.setNewOutputs(null);