if (values != null) {
            for (final String value : values.split(",")) {
                list.add(value);
            }
        }

        if (ResourceUtil.getResourceNoException("org/h2/Driver.class") != null) {
            list.add("h2");
        }

        if (ResourceUtil.getResourceNoException("com/mysql/jdbc/Driver.class") != null) {
            list.add("mysql");
        }

    @Override
    public ToolchainsBuildingResult build(ToolchainsBuildingRequest request) throws ToolchainsBuildingException {
        ProblemCollector problems = ProblemCollectorFactory.newInstance(null);

        PersistedToolchains globalToolchains = readToolchains(request.getGlobalToolchainsSource(), request, problems);

            }

            Arrays.sort(array, (o1, o2) -> {
                if (o1 == null && o2 == null) {
                    return 0;
                }
                if (o1 == null) {
                    return -1;
                }
                if (o2 == null) {
                    return 1;
                }

                final Object timeObj1 = o1.get(FieldNames.TIMESTAMP);

        .plus(String::class, "a")
        .plus(String::class, null)
        .plus(Integer::class, null)
        .plus(Boolean::class, null)
    assertThat(tags).isEqualTo(EmptyTags)
    assertThat(tags.toString()).isEqualTo("{}")
  }

  @Test
  fun removeAbsentFromEmpty() {
    val tags = EmptyTags.plus(String::class, null)
    assertThat(tags).isEqualTo(EmptyTags)

    Iterable<String> set = newHashSet("a", null, "b");
    assertTrue(FluentIterable.from(set).contains(null));
  }

  public void testContains_nullSetNo() {
    Iterable<String> set = ImmutableSortedSet.of("a", "b");
    assertFalse(FluentIterable.from(set).contains(null));
  }

  public void testContains_nullIterableYes() {
    Iterable<String> iterable = iterable("a", null, "b");

        assertEquals("http://test.com/sitemap.xml", removedSitemaps[1]);

        // Should be null after removal
        assertNull(crawlerContext.removeSitemaps());

        // Test with null
        crawlerContext.addSitemaps(null);
        assertNull(crawlerContext.removeSitemaps());

        // Test with empty array
        crawlerContext.addSitemaps(new String[0]);

            final CredentialsInternal renewed = renewable.renew();
            if (renewed != null) {
                this.creds = renewed;
                return true;
            }
        }
        final NtlmAuthenticator auth = NtlmAuthenticator.getDefault();
        if (auth != null) {
            final NtlmPasswordAuthenticator newAuth =

     * @param profile The (read-only) profile whose values should be injected, may be <code>null</code>.
     * @param request The model building request that holds further settings, must not be {@code null}.
     * @param problems The container used to collect problems that were encountered, must not be {@code null}.
     */

     * @param message The detail message of the problem, may be {@code null}.
     * @param line The one-based index of the line containing the problem or {@code -1} if unknown.
     * @param column The one-based index of the column containing the problem or {@code -1} if unknown.
     * @param cause The cause of the problem, may be {@code null}.
     */

public interface ToolchainManagerPrivate {

    /**
     * Retrieves every toolchains of given type available in user settings.
     *
     * @param type the type, must not be {@code null}
     * @param context the Maven session, must not be {@code null}
     * @since 3.0 (addition of the <code>MavenSession</code> parameter)
     */
    ToolchainPrivate[] getToolchainsForType(String type, MavenSession context) throws MisconfiguredToolchainException;