* from the runtime environment like {@link System#getProperties()} and environment variables.
     *
     * @param systemProperties The system properties, may be {@code null}.
     * @return This request, never {@code null}.
     */
    MavenExecutionRequest setSystemProperties(Properties systemProperties);

    /**

    assertFalse(table.contains("foo", 2));
    assertFalse(table.contains("bar", 3));
    assertFalse(table.contains("cat", 1));
    assertFalse(table.contains("foo", null));
    assertFalse(table.contains(null, 1));
    assertFalse(table.contains(null, null));
  }

  public void testContainsRow() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertTrue(table.containsRow("foo"));

        return "[ " + "FROM:("
                + (source == null ? "no source" : (source.md == null ? "no source MD" : source.md.toString())) + ") "
                + "TO:(" + (target == null ? "no target" : (target.md == null ? "no target MD" : target.md.toString()))
                + ") " + "version=" + version + ", scope=" + (scope == null ? "null" : scope.getScope()) + ", depth="
                + depth + "]";
    }

        if (jobExecutor == null) {
            throw new ScheduledJobException("No jobExecutor: " + scriptType);
        }

        if (!jobManager.findJobByUniqueOf(LaJobUnique.of(id)).isPresent()) {
            if (logger.isDebugEnabled()) {
                logger.debug("Job {} is running.", id);
            }
            return;
        }

        TimeoutTask task = null;
        try {

     * value is undefined.
     *
     * @return The location of the problem, never {@code null}.
     */
    String getLocation();

    /**
     * Gets the exception that caused this problem (if any).
     *
     * @return The exception that caused this problem or {@code null} if not applicable.
     */
    Exception getException();

    /**
     * Gets the message that describes this problem.

        for (Vertex v : children) {
            DfsState state = stateMap.putIfAbsent(v, DfsState.VISITING);
            if (state == null) {
                cycle.addLast(v.label);
                List<String> ret = visitCycle(v.children, stateMap, cycle);
                if (ret != null) {
                    return ret;
                }
                cycle.removeLast();
                stateMap.put(v, DfsState.VISITED);

    }

    public static UrlQueue<?> getUrlQueue() {
        return URL_QUEUE_THREAD_LOCAL.get();
    }

    public static void setUrlQueue(final UrlQueue<?> urlQueue) {
        if (urlQueue == null) {
            URL_QUEUE_THREAD_LOCAL.remove();
        } else {
            URL_QUEUE_THREAD_LOCAL.set(urlQueue);
        }
    }

    public static CrawlerContext getCrawlerContext() {

            try {
                final StatsObject data = statsCache.getIfPresent(key);
                if (data != null && data.decrement() <= 0) {
                    statsCache.invalidate(key);
                    final Long begin = data.remove(BEGIN_KEY);
                    if (begin != null) {
                        printStats(keyObj, data, begin, true);
                    }
                }

    // manually add elements to avoid expansion
    // 1/3 null keys, 1/3 null values
    int originalCount = 1024;
    InternalEntry<Object, Object, ?> entry = null;
    for (int i = 0; i < originalCount; i++) {
      Object key = new Object();
      Object value = (i % 3 == 0) ? null : new Object();
      int hash = map.hash(key);
      if (i % 3 == 1) {
        key = null;
      }

    // manually add elements to avoid expansion
    // 1/3 null keys, 1/3 null values
    int originalCount = 1024;
    InternalEntry<Object, Object, ?> entry = null;
    for (int i = 0; i < originalCount; i++) {
      Object key = new Object();
      Object value = (i % 3 == 0) ? null : new Object();
      int hash = map.hash(key);
      if (i % 3 == 1) {
        key = null;
      }