when (val protocol = sslSocket.applicationProtocol) {
        null, "" -> null
        else -> protocol
      }
    } catch (e: UnsupportedOperationException) {
      // https://docs.oracle.com/javase/9/docs/api/javax/net/ssl/SSLSocket.html#getApplicationProtocol--
      null
    }

  override fun trustManager(sslSocketFactory: SSLSocketFactory): X509TrustManager? {

  public void testRemove_unsupportedPresent() {
    assertThrows(UnsupportedOperationException.class, () -> getMap().remove(k0(), v0()));
    expectUnchanged();
  }

  @MapFeature.Require(absent = SUPPORTS_REMOVE)
  public void testRemove_unsupportedAbsent() {
    try {
      assertFalse(getMap().remove(k0(), v3()));
    } catch (UnsupportedOperationException tolerated) {

    List<V> values = singletonList(v3());
    assertThrows(UnsupportedOperationException.class, () -> multimap().replaceValues(k0(), values));
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  public void testReplaceValuesPutNotSupported() {
    List<V> values = singletonList(v3());
    assertThrows(UnsupportedOperationException.class, () -> multimap().replaceValues(k0(), values));
  }

          .put(TimeoutException.class, e -> e instanceof TimeoutException)
          .put(UnsupportedCharsetException.class, e -> e instanceof UnsupportedCharsetException)
          .put(UnsupportedOperationException.class, e -> e instanceof UnsupportedOperationException)
          .put(VerifyException.class, e -> e instanceof VerifyException)
          .putAll(PlatformSpecificExceptionBatch.PLATFORM.exceptions())
          .buildOrThrow();

  /*
   * absent = ZERO isn't required, since unmodList.add() must
   * throw regardless, but it keeps the method name accurate.
   */
  public void testAddAtIndex_unsupportedPresent() {
    assertThrows(UnsupportedOperationException.class, () -> getList().add(0, e0()));
    expectUnchanged();
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  public void testAddAtIndex_supportedNotPresent() {
    getList().add(0, e3());

    public boolean checkUserLoginable(final LoginCredential credential) {
        throw new UnsupportedOperationException("checkUserLoginable is not supported.");
    }

    @Override
    protected void checkCredential(final TypicalLoginAssist<String, FessUserBean, FessUser>.CredentialChecker checker) {
        throw new UnsupportedOperationException("checkCredential is not supported.");
    }

    @Override

      fail("Expected UnsupportedOperationException or NullPointerException.");
    } catch (UnsupportedOperationException | NullPointerException e) {
      // Expected.
    }
    assertInvariants(map);

    try {
      entrySet.addAll(singleton((Entry<K, V>) entryToAdd));
      fail("Expected UnsupportedOperationException or NullPointerException.");
    } catch (UnsupportedOperationException | NullPointerException e) {

                      }

                      @Override
                      public Iterator<String> iterator() {
                        throw new UnsupportedOperationException();
                      }

                      @Override
                      public boolean removeAll(Collection<?> collection) {
                        throw new UnsupportedOperationException();

      fail(message);
    } catch (UnsupportedOperationException expected) {
    }
  }

  private void expectReturnsFalseOrThrows(Target target) {
    String message = Platform.format("retainAll(%s) should return false or throw", target);
    try {
      assertFalse(message, collection.retainAll(target.toRetain));
    } catch (UnsupportedOperationException tolerated) {
    }
  }

    }

    override fun priority(
      streamId: Int,
      streamDependency: Int,
      weight: Int,
      exclusive: Boolean,
    ): Unit = throw UnsupportedOperationException()

    override fun pushPromise(
      streamId: Int,
      associatedStreamId: Int,
      headerBlock: List<Header>,
    ) {
      this.type = Http2.TYPE_PUSH_PROMISE