class FileChecker {

    public List<List<String>> checkFilesExistsWithPairs(final List<String> searchResult) {
        List<List<String>> result = new ArrayList<>();
        for (String actualFile : searchResult) {
            List<String> actualPair = new ArrayList<>();
            markFileIfNotExists(actualFile, actualPair); //adds actualFile to actualPair, mark it with "does not exist" if necessary
            String pairFile = getPair(actualFile);
            markFileIfNotExists(pairFile, actualPair); //adds pairFile to actualPair, mark it with "does not exist" if necessary
            result.add(actualPair);
        }
        return result;
    }

}