#vulnerable code 
                                @Override
    public <T> void unmarshal(Class<T> type, Consumer<? super T> consumer) {
        HSSFWorkbook workbook = (HSSFWorkbook) workbook();
        Optional<String> maybeSheetName = this.getSheetName(type, options);

        hssfFormulaEvaluator = HSSFFormulaEvaluator.create(workbook, null, null);
        Sheet sheet = this.getSheetToProcess(workbook, options, maybeSheetName.orElse(null));

        int skip = options.skip();
        int maxPhysicalNumberOfRows = sheet.getPhysicalNumberOfRows() + 1 - skip;

        loadColumnTitles(sheet, maxPhysicalNumberOfRows);
        AnnotationUtil.validateMandatoryNameColumns(options, type, columnIndexPerTitle.keySet());

        for (Row currentRow : sheet) {
            if (!skip(currentRow, skip) && !isRowEmpty(currentRow)) {
                internalCount += 1;

                if (limit != 0 && internalCount > limit)
                    return;

                T instance = deserializeRowToInstance(currentRow, type);
                consumer.accept(instance);
            }
        }
    } 
                            #location 10 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public <T> void unmarshal(Class<T> type, Consumer<? super T> consumer) {
        HSSFWorkbook workbook = (HSSFWorkbook) workbook();
        Optional<String> maybeSheetName = this.getSheetName(type, options);

        baseFormulaEvaluator = HSSFFormulaEvaluator.create(workbook, null, null);
        Sheet sheet = this.getSheetToProcess(workbook, options, maybeSheetName.orElse(null));

        processRowsToObjects(sheet, type, consumer);
    }