*/
  interface InternalEntry<K, V, E extends InternalEntry<K, V, E>> {
    /** Gets the next entry in the chain. */
    E getNext();

    /** Gets the entry's hash. */
    int getHash();

    /** Gets the key for this entry. */
    K getKey();

    /** Gets the value for the entry. */
    V getValue();
  }

  /*

   */
  interface InternalEntry<K, V, E extends InternalEntry<K, V, E>> {
    /** Gets the next entry in the chain. */
    E getNext();

    /** Gets the entry's hash. */
    int getHash();

    /** Gets the key for this entry. */
    K getKey();

    /** Gets the value for the entry. */
    V getValue();
  }

  /*

                buf.append('{');
                boolean first2 = true;
                for (final Map.Entry<String, Object> entry : doc.entrySet()) {
                    final String name = entry.getKey();
                    if (StringUtil.isNotBlank(name) && entry.getValue() != null) {
                        if (!first2) {
                            buf.append(',');
                        } else {

        List<Option> setPropertyOptions = new ArrayList<>();
        for (Option opt : mavenCli.getOptions()) {
            if (String.valueOf(CLIManager.SET_USER_PROPERTY).equals(opt.getOpt())) {
                setPropertyOptions.add(opt);
            } else {
                commandLineBuilder.addOption(opt);
            }
        }
        for (Option opt : mavenConfig.getOptions()) {

    assertFalse(map.containsKey(getKey));
    assertSame(refreshKey, map.get(refreshKey));

    // let computation complete
    letGetFinishSignal.countDown();
    getFinishedSignal.await();
    checkNothingLogged();

    // asMap view should have been updated
    assertEquals(2, cache.size());
    assertEquals(getKey + suffix, map.get(getKey));

                requireNonNull(e2);
                return comparator.compare(e1.getKey(), e2.getKey());
              });
          // requireNonNull is safe because the first `size` elements have been filled in.
          Entry<K, V> firstEntry = requireNonNull(entryArray[0]);
          K prevKey = firstEntry.getKey();
          keys[0] = prevKey;
          values[0] = firstEntry.getValue();

                        null,
                        "version of a plugin must be defined. ",
                        plugin);
            }

            String key = plugin.getKey();

            Plugin existing = index.get(key);

            if (existing != null) {
                addViolation(
                        problems,
                        errOn31,

                requireNonNull(e2);
                return comparator.compare(e1.getKey(), e2.getKey());
              });
          // requireNonNull is safe because the first `size` elements have been filled in.
          Entry<K, V> firstEntry = requireNonNull(entryArray[0]);
          K prevKey = firstEntry.getKey();
          keys[0] = prevKey;
          values[0] = firstEntry.getValue();

    Iterator<String> iterator = singletonList("foo").iterator();
    assertEquals("foo", Iterators.getNext(iterator, "bar"));
  }

  public void testGetNext_withDefault_empty() {
    Iterator<String> iterator = emptyIterator();
    assertEquals("bar", Iterators.getNext(iterator, "bar"));
  }

  public void testGetNext_withDefault_empty_null() {

            while ( chain != null ) {
                n++;
                int size = chain.size();
                int cost = chain.getCreditCost();
                CommonServerMessageBlockRequest next = chain.getNext();
                if ( log.isTraceEnabled() ) {
                    log.trace(
                        String.format("%s costs %d avail %d (%s)", chain.getClass().getName(), cost, this.credits.availablePermits(), this.name));