#vulnerable code 
                                private void migrateIndexerApiAccesses(Map<Integer, IndexerEntity> oldIdToIndexersMap) throws SQLException {
        Statement statement = connection.createStatement();
        int countIndexerApiAccesses = getCount(statement, "INDEXERAPIACCESS");
        logger.info("Migrating {} indexer API accesses from old database", countIndexerApiAccesses);
        eventPublisher.publishEvent(new MigrationMessageEvent("Migrating " + countIndexerApiAccesses + " indexer API access entries"));
        ResultSet oldIndexerApiAccesses = statement.executeQuery("SELECT * FROM INDEXERAPIACCESS");
        int countMigrated = 1;
        IndexerApiAccessEntity entity;
        ProgressLogger progressLogger = new ProgressLogger(logger, 5, TimeUnit.SECONDS);
        progressLogger.expectedUpdates = countIndexerApiAccesses;
        progressLogger.start();

        while (oldIndexerApiAccesses.next()) {
            entity = new IndexerApiAccessEntity();
            entity.setIndexer(oldIdToIndexersMap.get(oldIndexerApiAccesses.getInt("indexer_id")));
            entity.setTime(oldIndexerApiAccesses.getTimestamp("time").toInstant());
            Object responseTime = oldIndexerApiAccesses.getObject("response_time");
            entity.setResponseTime(responseTime != null ? ((Integer) responseTime).longValue() : null);
            String error = oldIndexerApiAccesses.getString("error");
            entity.setError(error != null ? error.substring(0, Math.min(4000, error.length())) : null);
            entity.setAccessType(null);
            entity.setResult(oldIndexerApiAccesses.getBoolean("response_successful") ? IndexerAccessResult.SUCCESSFUL : IndexerAccessResult.CONNECTION_ERROR); //Close enough
            entity.setAccessType(IndexerApiAccessType.valueOf(oldIndexerApiAccesses.getString("type").toUpperCase()));
            entityManager.persist(entity);
            progressLogger.lightUpdate();

            if (countMigrated++ % 50 == 0) {
                entityManager.flush();
                entityManager.clear();
            }
        }
        progressLogger.stop();
        statement.close();
        entityManager.flush();
        entityManager.clear();
        eventPublisher.publishEvent(new MigrationMessageEvent("Successfully migrated indexer API accesses from old database"));
        logger.info("Successfully migrated indexer API accesses from old database");
    } 
                            #location 23 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                private void migrateIndexerApiAccesses(Map<Integer, IndexerEntity> oldIdToIndexersMap) throws SQLException {
        Statement statement = connection.createStatement();
        int countIndexerApiAccesses = getCount(statement, "INDEXERAPIACCESS");
        logger.info("Migrating {} indexer API accesses from old database", countIndexerApiAccesses);
        eventPublisher.publishEvent(new MigrationMessageEvent("Migrating " + countIndexerApiAccesses + " indexer API access entries"));
        ResultSet oldIndexerApiAccesses = statement.executeQuery("SELECT * FROM INDEXERAPIACCESS");
        int countMigrated = 1;
        IndexerApiAccessEntity entity;
        ProgressLogger progressLogger = new ProgressLogger(logger, 5, TimeUnit.SECONDS);
        progressLogger.expectedUpdates = countIndexerApiAccesses;
        progressLogger.start();

        while (oldIndexerApiAccesses.next()) {
            entity = new IndexerApiAccessEntity();
            entity.setIndexer(oldIdToIndexersMap.get(oldIndexerApiAccesses.getInt("indexer_id")));
            entity.setTime(timestampToInstant(oldIndexerApiAccesses.getString("time")));
            Object responseTime = oldIndexerApiAccesses.getObject("response_time");
            entity.setResponseTime(responseTime != null ? ((Integer) responseTime).longValue() : null);
            String error = oldIndexerApiAccesses.getString("error");
            entity.setError(error != null ? error.substring(0, Math.min(4000, error.length())) : null);
            entity.setAccessType(null);
            entity.setResult(oldIndexerApiAccesses.getBoolean("response_successful") ? IndexerAccessResult.SUCCESSFUL : IndexerAccessResult.CONNECTION_ERROR); //Close enough
            entity.setAccessType(IndexerApiAccessType.valueOf(oldIndexerApiAccesses.getString("type").toUpperCase()));
            entityManager.persist(entity);
            progressLogger.lightUpdate();

            if (countMigrated++ % 50 == 0) {
                entityManager.flush();
                entityManager.clear();
            }
        }
        progressLogger.stop();
        statement.close();
        entityManager.flush();
        entityManager.clear();
        eventPublisher.publishEvent(new MigrationMessageEvent("Successfully migrated indexer API accesses from old database"));
        logger.info("Successfully migrated indexer API accesses from old database");
    }