public Path combineStringOffsetAndEntryFile() throws IOException {
        FileChannel entryFile = FileChannel.open(
                entryFilePath,
                StandardOpenOption.READ);
        FileChannel entryOffsetFile = FileChannel.open(
                entryOffsetFilePath,
                StandardOpenOption.READ);
        Path path = dir.resolve("str");
        FileChannel stringsFile = FileChannel.open(
                path,
                StandardOpenOption.WRITE,
                StandardOpenOption.CREATE,
                StandardOpenOption.TRUNCATE_EXISTING);

        ByteBuffer entryFileBuffer = entryFile.map(FileChannel.MapMode.READ_ONLY, 0, entryFile.size());
        ByteBuffer entryOffsetFileBuffer = entryOffsetFile.map(FileChannel.MapMode.READ_ONLY, 0, entryOffsetFile.size());

        try {
            stringsFile.write(entryOffsetFileBuffer);
            stringsFile.write(entryFileBuffer);
        } finally {
            IOUtil.closeQuietly(entryFile);
            IOUtil.closeQuietly(entryOffsetFile);
            Try.on(() -> stringsFile.force(false), logger);
            IOUtil.closeQuietly(stringsFile);
        }
        return path;
    }
Delete all files generated by this class.
indexr-vlt-segment/src/main/java/io/indexr/vlt/segment/index/DictMerge.java