#fixed code
                             public static File unBZip2(File archive, String export) throws IOException {
		Archiver archiver = ArchiverFactory.createArchiver(ArchiveFormat.TAR,
				CompressionType.BZIP2);
		archiver.extract(archive, archive.getParentFile());
		log.trace("Unbzip2 {}", archive);
		File target = checkPhantom(archive, export);

		return target;
	}
#vulnerable code 
                             public static File unBZip2(File archive, String export) throws IOException {
		Archiver archiver = ArchiverFactory.createArchiver(ArchiveFormat.TAR,
				CompressionType.BZIP2);
		archiver.extract(archive, archive.getParentFile());
		log.trace("Unbzip2 {}", archive);
		File target;

		String phantomjsName = "phantomjs";
		if (export.contains(phantomjsName)) {
			String fileNoExtension = archive.getName().replace(".tar.bz2", "");
			File phantomjs = new File(archive.getParentFile().getAbsolutePath()
					+ File.separator + fileNoExtension + File.separator + "bin"
					+ File.separator + phantomjsName);
			target = new File(archive.getParentFile().getAbsolutePath()
					+ File.separator + phantomjsName);
			phantomjs.renameTo(target);

			File delete = new File(archive.getParentFile().getAbsolutePath()
					+ File.separator + fileNoExtension);
			log.trace("Folder to be deleted: {}", delete);
			FileUtils.deleteDirectory(delete);
		} else {
			target = archive.getParentFile().listFiles()[0];
		}

		return target;
	} 
                            #location 23 
                            #vulnerability type NULL_DEREFERENCE