private final URL url;

    private DfsReferralData dfsReferral = null; // For getDfsPath() and getServerWithDfs()

    private String unc; // Initially null; set by getUncPath; never ends with '/'
    private String uncBeforeDfsReferal;
    private String canon; // Initially null; set by getUncPath; dir must end with '/'
    private String share; // Can be null

    private Address[] addresses;
    private int addressIndex;

        this.lookup = requireNonNull(lookup, "lookup cannot be null");
        this.languageRegistry = requireNonNull(languageRegistry, "languageRegistry cannot be null");
        this.usedTypes = new ConcurrentHashMap<>();
        this.manager = requireNonNull(manager, "artifactHandlerManager cannot be null");
    }

    @Override
    public void onEvent(Object event) {

        // Test hashCode with null input - should not throw, returns consistent hash for null
        ProtwordsItem item1 = new ProtwordsItem(1, null);
        ProtwordsItem item2 = new ProtwordsItem(2, null);

        // Should not throw
        int hash1 = item1.hashCode();
        int hash2 = item2.hashCode();

        // Same null input should produce same hashCode
        assertEquals(hash1, hash2);

     * @return the removed entry, or {@literal null} if there was no entry for the key
     */
    protected Entry<K, V> removeMap(final Object key) {
        int hashCode = 0;
        int index = 0;

        if (key != null) {
            hashCode = key.hashCode();
            index = (hashCode & 0x7FFFFFFF) % mapTable.length;
            for (Entry<K, V> e = mapTable[index], prev = null; e != null; prev = e, e = e.next) {

    assertNull("getOrDefault(absent, null) should return null", getMap().getOrDefault(k3(), null));
  }

  @MapFeature.Require(ALLOWS_NULL_KEY_QUERIES)
  public void testGetOrDefault_absentNull() {
    assertEquals(
        "getOrDefault(null, def) should return the default value",
        v3(),
        getMap().getOrDefault(null, v3()));
  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEY_QUERIES)

            getMap()
                .computeIfAbsent(
                    null,
                    k -> {
                      assertNull(k);
                      return v3();
                    }));
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported computeIfAbsent(null, function)");
  }

        this.syncContextFactory = Objects.requireNonNull(syncContextFactory, "syncContextFactory cannot be null");
        this.repositoryEventDispatcher =
                Objects.requireNonNull(repositoryEventDispatcher, "repositoryEventDispatcher cannot be null");
        this.versionScheme = Objects.requireNonNull(versionScheme, "versionScheme cannot be null");
    }

    @Override

    return rowKey != null && safeContainsKey(backingMap, rowKey);
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return value != null && super.containsValue(value);
  }

  @Override
  public @Nullable V get(@Nullable Object rowKey, @Nullable Object columnKey) {
    return (rowKey == null || columnKey == null) ? null : super.get(rowKey, columnKey);
  }

        assertEquals(-1, problem.getColumnNumber());

        problem = new DefaultProblem(null, null, null, -1, 42, null);
        assertEquals(42, problem.getColumnNumber());

        problem = new DefaultProblem(null, null, null, -1, Integer.MAX_VALUE, null);
        assertEquals(Integer.MAX_VALUE, problem.getColumnNumber());

        // this case is not specified, might also return -1

      getMap().putIfAbsent(k0(), null);
    } catch (NullPointerException tolerated) {
    }
    expectUnchanged();
    expectNullValueMissingWhenNullValuesUnsupported(
        "Should not contain null after unsupported putIfAbsent(present, null)");
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_VALUES})
  public void testPut_nullValueSupported() {
    Entry<K, V> nullValueEntry = entry(k3(), null);
    assertNull(