Converter<String, Number> converter = Converter.<String, Number>from(forward, backward);

    assertNull(converter.convert(null));
    assertNull(converter.reverse().convert(null));

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

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

            this.clock_seq_low = (byte) _src.dec_ndr_small();
            final int _nodes = 6;
            final int _nodei = _src.index;
            _src.advance(1 * _nodes);

            if (this.node == null) {
                if (_nodes < 0 || _nodes > 0xFFFF) {
                    throw new NdrException(NdrException.INVALID_CONFORMANCE);
                }
                this.node = new byte[_nodes];
            }

        /**
         * @return String
         */
        public String getAaa() {
            return null;
        }

        /**
         * @param a
         * @return String
         */
        public String getBbb(final Object a) {
            return null;
        }

        /**
         * @return boolean
         */
        public boolean isCCC() {

            return null;
        }
    }

    /**
     * If the class is a primitive type, returns its wrapper class.
     *
     * @param className
     *            The class name. Must not be {@literal null} or empty.
     * @return {@link Class}
     * @throws EmptyArgumentException
     *             If the class name is {@literal null} or empty.

    }

    public void myspecifyPropertyCancel(String propertyName) {
        if (__specifiedProperties != null) {
            __specifiedProperties.remove(propertyName);
        }
    }

    public void clearSpecifiedInfo() {
        if (__specifiedProperties != null) {
            __specifiedProperties.clear();
        }
    }

    protected void checkSpecifiedProperty(String propertyName) {

    private String getResourceName(final ResponseData responseData) {
        String name = responseData.getUrl();
        final String enc = responseData.getCharSet();

        if (name == null || enc == null) {
            return null;
        }

        name = name.replaceAll("/+$", "");
        final int idx = name.lastIndexOf('/');
        if (idx >= 0) {
            name = name.substring(idx + 1);
        }

    // https://daniel.haxx.se/blog/2016/08/18/http2-connection-coalescing/

    // 1. This connection must be HTTP/2.
    if (http2Connection == null) return false

    // 2. The routes must share an IP address.
    if (routes == null || !routeMatchesAny(routes)) return false

    // 3. This connection's server certificates must cover the new host.

    }

    @Test
    void testNullValues() {
        RequestTrace trace = new RequestTrace(null, null, null);
        assertNull(trace.context());
        assertNull(trace.parent());
        assertNull(trace.data());
    }

    @Test
    void testChainedTraces() {
        RequestTrace root = new RequestTrace("root", null, "root-data");
        RequestTrace level1 = new RequestTrace("level1", root, "level1-data");

    /**
     * Creates an artifact.
     *
     * @param request the request holding artifact creation parameters
     * @return an {@code Artifact}, never {@code null}
     * @throws IllegalArgumentException if {@code request} is null or {@code request.session} is null or invalid
     */
    @Nonnull
    Artifact create(@Nonnull ArtifactFactoryRequest request);

    @Nonnull
    default Artifact create(

    } 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