#fixed code
                                protected void buildResources(PdfDictionary dictionary) throws PdfException {
        for (PdfName resourceType : dictionary.keySet()) {
            if (nameToResource.get(resourceType) == null) {
                nameToResource.put(resourceType, new HashMap<PdfName, PdfObject>());
            }
            PdfDictionary resources = dictionary.getAsDictionary(resourceType);
            if (resources == null)
                continue;
            for (PdfName resourceName : resources.keySet()) {
                PdfObject resource = resources.get(resourceName, false);
                resourceToName.put(resource, resourceName);
                nameToResource.get(resourceType).put(resourceName, resource);
            }
        }
        Set<PdfName> names = getResourceNames();
        fontNumber = getAvailableNumber(names, F);
        imageNumber = getAvailableNumber(names, Im);
        formNumber = getAvailableNumber(names, Fm);
        egsNumber = getAvailableNumber(names, Gs);
        propNumber = getAvailableNumber(names, Pr);
        csNumber = getAvailableNumber(names, Cs);
    }
#vulnerable code 
                                protected void buildResources(PdfDictionary dictionary) throws PdfException {
        for (PdfName resourceType : dictionary.keySet()) {
            if (nameToResource.get(resourceType) == null) {
                nameToResource.put(resourceType, new HashMap<PdfName, PdfObject>());
            }
            PdfDictionary resources = dictionary.getAsDictionary(resourceType);
            for (PdfName resourceName : resources.keySet()) {
                PdfObject resource = resources.get(resourceName, false);
                resourceToName.put(resource, resourceName);
                nameToResource.get(resourceType).put(resourceName, resource);
            }
        }
        Set<PdfName> names = getResourceNames();
        fontNumber = getAvailableNumber(names, F);
        imageNumber = getAvailableNumber(names, Im);
        formNumber = getAvailableNumber(names, Fm);
        egsNumber = getAvailableNumber(names, Gs);
        propNumber = getAvailableNumber(names, Pr);
        csNumber = getAvailableNumber(names, Cs);
    } 
                            #location 7 
                            #vulnerability type NULL_DEREFERENCE