#vulnerable code 
                                @Procedure(name = "ga.nlp.parser.pdf")
    public Stream<Page> parsePdf(@Name("file") String filename, @Name(value = "filterPatterns", defaultValue = "") List<String> filterPatterns) {
        TikaPDFParser parser = (TikaPDFParser) getNLPManager().getExtension(TikaPDFParser.class);
        List<String> filters = filterPatterns.equals("") ? new ArrayList<>() : filterPatterns;
        try {
            List<Page> pages = parser.parse(filename, filters);

            return pages.stream();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    } 
                            #location 6 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Procedure(name = "ga.nlp.parser.pdf")
    public Stream<Page> parsePdf(@Name("file") String filename, @Name(value = "filterPatterns", defaultValue = "") List<String> filterPatterns) {
        TikaPDFParser parser = (TikaPDFParser) getNLPManager().getExtension(TikaPDFParser.class);

        return getPages(parser, filename, filterPatterns).stream();
    }