* into a repository. In the first case, the result needs to be a proper local repository that one can use for
         * local artifact resolution. In the second case, the result needs to precisely obey the path information of the
         * repository's layout to allow pointing at artifacts within the repository. Unfortunately,

        if (threads <= 1) {
            executor = Runnable::run;
        } else {
            executor = new ThreadPoolExecutor(
                    threads, threads, 3, TimeUnit.SECONDS, new LinkedBlockingQueue<>(), new DaemonThreadCreator());
        }
    }

    private RepositorySystemSession getSession(ArtifactRepository localRepository) {

        requests.clear();

        PluginPrefixResult result = processResults(request, trace, results, requests);

        if (result != null) {
            return result;
        }

        // second try, refetch all (possibly outdated) metadata that wasn't updated in the first attempt

        if (!request.getRepositorySession().isOffline() && !requests.isEmpty()) {

        printErrors(result);

        Iterator<Artifact> i = result.getArtifacts().iterator();
        assertEquals(n, i.next(), "n should be first");
        assertEquals(m, i.next(), "m should be second");

        // inverse order
        set = new LinkedHashSet<>();
        set.add(m);
        set.add(n);

        result = artifactResolver.resolveTransitively(

            return value;
        }
    }

    /**
     * Represents a combination in the version item list.
     * It is usually a combination of a string and a number, with the string first and the number second.
     */
    private static class CombinationItem implements Item {

        StringItem stringPart;

        Item digitPart;

        CombinationItem(String value) {
            int index = 0;

            // this will run at most twice. The first time, the firstRun flag is turned off, and if the retry flag
            // is set on the first run, it will be turned off and not re-set on the second try. This is because the
            // only way the retry flag can be set is if ( firstRun == true ).
            while (firstRun || retry) {
                ChecksumObserver md5ChecksumObserver = null;

/**
 * A request to collect the transitive dependencies and to build a dependency graph from them. There are three ways to
 * create a dependency graph. First, only the root dependency can be given. Second, a root dependency and direct
 * dependencies can be specified in which case the specified direct dependencies are merged with the direct dependencies