#fixed code
                                @Override
    @Cacheable("attachment-cache")
    public Attachment findAttachmentById(String attachmentId) {
        if (attachmentId == null) {
            return null;
        }
        if (log.isDebugEnabled()) {
            log.debug("Finding attachment : " + attachmentId);
        }
        Attachment attachment = this.findAttachmentMetadataById(attachmentId);

        if (attachment == null) {
            return null;
        }

        ColumnQuery<String, String, byte[]> queryAttachment = HFactory.createColumnQuery(keyspaceOperator,
                StringSerializer.get(), StringSerializer.get(), BytesArraySerializer.get());

        HColumn<String, byte[]> columnAttachment =
                queryAttachment.setColumnFamily(ATTACHMENT_CF)
                        .setKey(attachmentId)
                        .setName(CONTENT)
                        .execute()
                        .get();

        attachment.setContent(columnAttachment.getValue());
        return attachment;
    }
#vulnerable code 
                                @Override
    @Cacheable("attachment-cache")
    public Attachment findAttachmentById(String attachmentId) {
        if (attachmentId == null) {
            return null;
        }
        if (log.isDebugEnabled()) {
            log.debug("Finding attachment : " + attachmentId);
        }
        Attachment attachment = this.findAttachmentMetadataById(attachmentId);

        ColumnQuery<String, String, byte[]> queryAttachment = HFactory.createColumnQuery(keyspaceOperator,
                StringSerializer.get(), StringSerializer.get(), BytesArraySerializer.get());

        HColumn<String, byte[]> columnAttachment =
                queryAttachment.setColumnFamily(ATTACHMENT_CF)
                        .setKey(attachmentId)
                        .setName(CONTENT)
                        .execute()
                        .get();

        attachment.setContent(columnAttachment.getValue());
        return attachment;
    } 
                            #location 22 
                            #vulnerability type NULL_DEREFERENCE