assertThat(converter.convert(null)).isNull();
    assertThat(converter.reverse().convert(null)).isNull();

    assertEquals((Integer) 5, converter.convert("5"));
    assertThat(converter.reverse().convert(5)).isEqualTo("5");
  }

  // Null-passthrough violates our nullness annotations, so we don't support it under J2KT.
  @J2ktIncompatible

  public void testContainsEntryWithNullKeyAbsent() {
    assertFalse(getMap().entrySet().contains(mapEntry(null, v0())));
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testContainsEntryWithNullKeyPresent() {
    initMapWithNullKey();
    assertTrue(getMap().entrySet().contains(mapEntry(null, getValueForNullKey())));
  }

  @MapFeature.Require(ALLOWS_NULL_VALUE_QUERIES)

  public void testContainsEntryWithNullKeyAbsent() {
    assertFalse(getMap().entrySet().contains(mapEntry(null, v0())));
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testContainsEntryWithNullKeyPresent() {
    initMapWithNullKey();
    assertTrue(getMap().entrySet().contains(mapEntry(null, getValueForNullKey())));
  }

  @MapFeature.Require(ALLOWS_NULL_VALUE_QUERIES)

    try {
      val provider = Proxy.getInvocationHandler(getMethod.invoke(null, sslSocket)) as AlpnProvider
      if (!provider.unsupported && provider.selected == null) {
        log("ALPN callback dropped: HTTP/2 is disabled. " + "Is alpn-boot on the boot class path?")
        return null
      }
      return if (provider.unsupported) null else provider.selected
    } catch (e: InvocationTargetException) {

                    break;
                }
            }
            if (this.authMethod == null) {
                return null;
            }
            NtlmMessage message = authorization != null ? new Type2Message(Base64.decode(authorization)) : null;
            reconnect();
            if (message == null) {
                message = new Type1Message(this.transportContext);

                    parameters = null,
                  ),
                subjectPublicKey =
                  BitString(
                    byteString = publicKeyBytes,
                    unusedBitsCount = 0,
                  ),
              ),
            issuerUniqueID = null,
            subjectUniqueID = null,
            extensions = listOf(),
          ),

        if (CACHE_POLICY == 0) {
            return null;
        }
        synchronized (ADDRESS_CACHE) {
            CacheEntry entry = (CacheEntry) ADDRESS_CACHE.get(hostName);
            if (entry != null && entry.expiration < System.currentTimeMillis() && entry.expiration >= 0) {
                entry = null;
            }
            return entry != null ? entry.address : null;
        }
    }

  public void testImmutableEntryNull() {
    Entry<@Nullable String, @Nullable Integer> e = immutableEntry((String) null, (Integer) null);
    assertThat(e.getKey()).isNull();
    assertThat(e.getValue()).isNull();
    assertThrows(UnsupportedOperationException.class, () -> e.setValue(null));
    assertThat(e.toString()).isEqualTo("null=null");
    assertEquals(0, e.hashCode());
  }

    }

    @Test
    @DisplayName("Should handle null message")
    void testNullMessage() {
        // When/Then
        assertDoesNotThrow(() -> {
            CIFSException exception = new CIFSException((String) null);
            assertNotNull(exception);
        });
    }

    @Test
    @DisplayName("Should handle null cause")
    void testNullCause() {
        // When/Then

     * @param field The key of the field, must not be
     * <code>null</code>.
     * @return The location of the field in the input source or
     * <code>null</code> if unknown.
     */
    public InputLocation getLocation(Object field);
    /**
     * Sets the location of the specified field.
     *
     * @param field The key of the field, must not be
     * <code>null</code>.
     * @param location The location of the field, may be