#vulnerable code 
                                public static void load(final JanusGraph graph, final int rowsToLoad, final boolean report)
        throws IOException, InterruptedException {

        final JanusGraphManagement mgmt = graph.openManagement();
        if (mgmt.getGraphIndex(CHARACTER) == null) {
            final PropertyKey characterKey = mgmt.makePropertyKey(CHARACTER).dataType(String.class).make();
            mgmt.buildIndex(CHARACTER, Vertex.class).addKey(characterKey).unique().buildCompositeIndex();
        }
        if (mgmt.getGraphIndex(COMIC_BOOK) == null) {
            final PropertyKey comicBookKey = mgmt.makePropertyKey(COMIC_BOOK).dataType(String.class).make();
            mgmt.buildIndex(COMIC_BOOK, Vertex.class).addKey(comicBookKey).unique().buildCompositeIndex();
            mgmt.makePropertyKey(WEAPON).dataType(String.class).make();
            mgmt.makeEdgeLabel(APPEARED).multiplicity(Multiplicity.MULTI).make();
        }
        mgmt.commit();

        final ClassLoader classLoader = MarvelGraphFactory.class.getClassLoader();
        final URL resource = classLoader.getResource("META-INF/marvel.csv");
        Preconditions.checkNotNull(resource);
        final Map<String, Set<String>> comicToCharacter = new HashMap<>();
        final Map<String, Set<String>> characterToComic = new HashMap<>();
        final Set<String> characters = new HashSet<>();
        final BlockingQueue<Runnable> creationQueue = new LinkedBlockingQueue<>();
        try (CSVReader reader = new CSVReader(new InputStreamReader(resource.openStream()))) {
            reader.readAll().subList(0, rowsToLoad).forEach(nextLine -> {
                final String comicBook = nextLine[1];
                final String[] characterNames = nextLine[0].split("/");
                if (!comicToCharacter.containsKey(comicBook)) {
                    comicToCharacter.put(comicBook, new HashSet<>());
                }
                final List<String> comicCharacters = Arrays.asList(characterNames);
                comicToCharacter.get(comicBook).addAll(comicCharacters);
                characters.addAll(comicCharacters);
            });
        }
        creationQueue.addAll(characters.stream().map(character -> new CharacterCreationCommand(character, graph))
            .collect(Collectors.toList()));

        final BlockingQueue<Runnable> appearedQueue = new LinkedBlockingQueue<>();
        for (String comicBook : comicToCharacter.keySet()) {
            creationQueue.add(new ComicBookCreationCommand(comicBook, graph));
            final Set<String> comicCharacters = comicToCharacter.get(comicBook);
            for (String character : comicCharacters) {
                final AppearedCommand lineCommand = new AppearedCommand(graph, new Appeared(character, comicBook));
                appearedQueue.add(lineCommand);
                if (!characterToComic.containsKey(character)) {
                    characterToComic.put(character, new HashSet<String>());
                }
                characterToComic.get(character).add(comicBook);
            }
            REGISTRY.histogram("histogram.comic-to-character").update(comicCharacters.size());
        }

        int maxAppearances = 0;
        String maxCharacter = "";
        for (String character : characterToComic.keySet()) {
            final Set<String> comicBookSet = characterToComic.get(character);
            final int numberOfAppearances = comicBookSet.size();
            REGISTRY.histogram("histogram.character-to-comic").update(numberOfAppearances);
            if (numberOfAppearances > maxAppearances) {
                maxCharacter = character;
                maxAppearances = numberOfAppearances;
            }
        }
        log.info("Character {} has most appearances at {}", maxCharacter, maxAppearances);

        ExecutorService executor = Executors.newFixedThreadPool(POOL_SIZE);
        for (int i = 0; i < POOL_SIZE; i++) {
            executor.execute(new BatchCommand(graph, creationQueue));
        }
        executor.shutdown();
        while (!executor.awaitTermination(TIMEOUT_SIXTY_SECONDS, TimeUnit.SECONDS)) {
            log.info("Awaiting:" + creationQueue.size());
            if (report) {
                REPORTER.report();
            }
        }

        executor = Executors.newSingleThreadExecutor();
        executor.execute(new BatchCommand(graph, appearedQueue));

        executor.shutdown();
        while (!executor.awaitTermination(TIMEOUT_SIXTY_SECONDS, TimeUnit.SECONDS)) {
            log.info("Awaiting:" + appearedQueue.size());
            if (report) {
                REPORTER.report();
            }
        }
        log.info("MarvelGraph.load complete");
    } 
                            #location 43 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public static void load(final JanusGraph graph, final int rowsToLoad, final boolean report)
        throws IOException, InterruptedException {

        final JanusGraphManagement mgmt = graph.openManagement();
        if (mgmt.getGraphIndex(CHARACTER) == null) {
            final PropertyKey characterKey = mgmt.makePropertyKey(CHARACTER).dataType(String.class).make();
            mgmt.buildIndex(CHARACTER, Vertex.class).addKey(characterKey).unique().buildCompositeIndex();
        }
        if (mgmt.getGraphIndex(COMIC_BOOK) == null) {
            final PropertyKey comicBookKey = mgmt.makePropertyKey(COMIC_BOOK).dataType(String.class).make();
            mgmt.buildIndex(COMIC_BOOK, Vertex.class).addKey(comicBookKey).unique().buildCompositeIndex();
            mgmt.makePropertyKey(WEAPON).dataType(String.class).make();
            mgmt.makeEdgeLabel(APPEARED).multiplicity(Multiplicity.MULTI).make();
        }
        mgmt.commit();

        final ClassLoader classLoader = MarvelGraphFactory.class.getClassLoader();
        final URL resource = classLoader.getResource("META-INF/marvel.csv");
        Preconditions.checkNotNull(resource);
        final Map<String, Set<String>> comicToCharacter = new HashMap<>();
        final Map<String, Set<String>> characterToComic = new HashMap<>();
        final Set<String> characters = new HashSet<>();
        final BlockingQueue<Runnable> creationQueue = new LinkedBlockingQueue<>();
        try (CSVReader reader = new CSVReader(new InputStreamReader(resource.openStream(), Charset.forName("UTF-8")))) {
            reader.readAll().subList(0, rowsToLoad).forEach(nextLine -> {
                final String comicBook = nextLine[1];
                final String[] characterNames = nextLine[0].split("/");
                if (!comicToCharacter.containsKey(comicBook)) {
                    comicToCharacter.put(comicBook, new HashSet<>());
                }
                final List<String> comicCharacters = Arrays.asList(characterNames);
                comicToCharacter.get(comicBook).addAll(comicCharacters);
                characters.addAll(comicCharacters);
            });
        }
        creationQueue.addAll(characters.stream().map(character -> new CharacterCreationCommand(character, graph))
            .collect(Collectors.toList()));

        final BlockingQueue<Runnable> appearedQueue = new LinkedBlockingQueue<>();
        for (Map.Entry<String, Set<String>> entry : comicToCharacter.entrySet()) {
            final String comicBook = entry.getKey();
            final Set<String> comicCharacters = entry.getValue();
            creationQueue.add(new ComicBookCreationCommand(comicBook, graph));
            for (String character : comicCharacters) {
                final AppearedCommand lineCommand = new AppearedCommand(graph, new Appeared(character, comicBook));
                appearedQueue.add(lineCommand);
                if (!characterToComic.containsKey(character)) {
                    characterToComic.put(character, new HashSet<String>());
                }
                characterToComic.get(character).add(comicBook);
            }
            REGISTRY.histogram("histogram.comic-to-character").update(comicCharacters.size());
        }

        int maxAppearances = 0;
        String maxCharacter = "";
        for (Map.Entry<String, Set<String>> entry : characterToComic.entrySet()) {
            final String character = entry.getKey();
            final Set<String> comicBookSet = entry.getValue();
            final int numberOfAppearances = comicBookSet.size();
            REGISTRY.histogram("histogram.character-to-comic").update(numberOfAppearances);
            if (numberOfAppearances > maxAppearances) {
                maxCharacter = character;
                maxAppearances = numberOfAppearances;
            }
        }
        log.info("Character {} has most appearances at {}", maxCharacter, maxAppearances);

        ExecutorService executor = Executors.newFixedThreadPool(POOL_SIZE);
        for (int i = 0; i < POOL_SIZE; i++) {
            executor.execute(new BatchCommand(graph, creationQueue));
        }
        executor.shutdown();
        while (!executor.awaitTermination(TIMEOUT_SIXTY_SECONDS, TimeUnit.SECONDS)) {
            log.info("Awaiting:" + creationQueue.size());
            if (report) {
                REPORTER.report();
            }
        }

        executor = Executors.newSingleThreadExecutor();
        executor.execute(new BatchCommand(graph, appearedQueue));

        executor.shutdown();
        while (!executor.awaitTermination(TIMEOUT_SIXTY_SECONDS, TimeUnit.SECONDS)) {
            log.info("Awaiting:" + appearedQueue.size());
            if (report) {
                REPORTER.report();
            }
        }
        log.info("MarvelGraph.load complete");
    }