} catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().removeAll(null) doesn't throws NPE.
    }
  }

  @Override
  public void testEntrySetRetainAllNullFromEmpty() {
    try {
      super.testEntrySetRetainAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().retainAll(null) doesn't throws NPE.
    }
  }

  @Override

public interface VersionParser extends Service {

    /**
     * Parses the specified version string, for example "1.0".
     *
     * @param version the version string to parse, must not be {@code null}
     * @return the parsed version, never {@code null}
     * @throws VersionParserException if the string violates the syntax rules of this scheme
     * @see org.apache.maven.api.Session#parseVersion(String)
     */
    @Nonnull

        checkNotClosed();

        if (key == null || sessionId == null) {
            throw new IllegalArgumentException("Session ID and key must not be null");
        }

        // Clone the key to prevent external modification
        byte[] keyClone = key.clone();
        SecretKey secretKey = new SecretKeySpec(keyClone, algorithm);

        // Store in memory

     * @param url the URL to convert
     * @return the converted URL after applying all duplicate host rules,
     *         or null if the input URL is null
     */
    public String convert(final String url) {
        if (url == null) {
            return null;
        }

        if (duplicateHostList == null) {
            init();
        }

        String newUrl = url;

     */
    public PACDecodingException() {
        this(null, null);
    }

    /**
     * Constructs a new PAC decoding exception with the specified detail message.
     * @param message the detail message
     */
    public PACDecodingException(final String message) {
        this(message, null);
    }

    /**
     * Constructs a new PAC decoding exception with the specified cause.

    public void test_nullHandling() {
        // Test with null ParseException
        QueryParseException queryParseException = new QueryParseException(null);
        assertNotNull(queryParseException);
        assertNull(queryParseException.getCause());
        // getMessage() may return null when constructed with null
        // This is expected behavior for exceptions with null cause
    }

    public void test_nestedCause() {

     * Constructs an instance.
     *
     * @param clazz
     *            the class (must not be {@literal null})
     */
    public ClassIterator(final Class<?> clazz) {
        this(clazz, true);
    }

    /**
     * Constructs an instance.
     *
     * @param clazz the class (must not be {@literal null})
     * @param includeObject if {@literal true}, includes the {@link Object} class in the iteration
     */

     * @param keyList The list of keys to register this extractor under.
     */
    public void register(final List<String> keyList) {
        if (keyList == null || keyList.isEmpty()) {
            throw new IllegalArgumentException("keyList must not be null or empty.");
        }
        getExtractorFactory().addExtractor(keyList, this);
    }

    /**
     * Returns the MimeTypeHelper instance from the CrawlerContainer.

        assertNotNull(defaultConfig.getRandom(), "Random should not be null");
        assertNotNull(defaultConfig.getLocalTimezone(), "Local timezone should not be null");
        assertNotNull(defaultConfig.getMachineId(), "Machine ID should not be null");
    }

    @Test
    @DisplayName("Test network configuration getters")
    void testNetworkConfigurationGetters() {

        assertEquals("abcd", normalizer.normalize("ａｂｃｄ", null));
        assertEquals("みかん", normalizer.normalize("みかん", null));
        assertEquals("みかん ﾘﾝｺﾞ", normalizer.normalize("みかん　リンゴ", null));
    }

    public void test_AnyLower() {
        ICUNormalizer normalizer = new ICUNormalizer("Any-Lower");
        assertEquals("abcd", normalizer.normalize("ABCD", null));
    }

    public void test_HalfwidthFullwidth() {