startPosition = fessConfig.getPagingSearchPageStartAsInteger();
            } else {
                try {
                    startPosition = Integer.parseInt(start);
                } catch (final NumberFormatException e) {
                    startPosition = fessConfig.getPagingSearchPageStartAsInteger();
                }
            }
            return startPosition;
        }

        @Override

                        try {
                            DfTypeUtil.toLong(s);
                        } catch (final NumberFormatException e) {
                            consumer.accept(attrName);
                        }
                    }));
        } else {
            // do nothing
        }
    }

    /**

        final String value = getSystemProperty(key);
        if (value != null) {
            try {
                return Integer.parseInt(value);
            } catch (final NumberFormatException e) {
                // ignore
            }
        }
        return defaultValue;
    }

    default void setSystemPropertyAsInt(final String key, final int value) {

        final String value = namedItem.getTextContent();
        if (value == null) {
            return null;
        }
        try {
            return Integer.parseInt(value);
        } catch (final NumberFormatException e) {
            if (value.endsWith("%") || value.endsWith("px")) {
                return null;
            }
            return 0;
        }
    }

    /**

              @Override
              public Integer apply(String from) {
                return Integer.valueOf(from);
              }
            });

    result.next();
    assertThrows(NumberFormatException.class, () -> result.next());
  }

  public void testNullFriendlyTransform() {
    Iterator<@Nullable Integer> input = Arrays.<@Nullable Integer>asList(1, 2, null, 3).iterator();
    Iterator<String> result =

              @Override
              public Integer apply(String from) {
                return Integer.valueOf(from);
              }
            });

    result.next();
    assertThrows(NumberFormatException.class, () -> result.next());
  }

  public void testNullFriendlyTransform() {
    Iterator<@Nullable Integer> input = Arrays.<@Nullable Integer>asList(1, 2, null, 3).iterator();
    Iterator<String> result =

        val portString = input.canonicalize(pos = pos, limit = limit, encodeSet = "")
        val i = portString.toInt()
        if (i in 1..65535) i else -1
      } catch (_: NumberFormatException) {
        -1 // Invalid port.
      }
  }

  companion object {
    /** Returns 80 if `scheme.equals("http")`, 443 if `scheme.equals("https")` and -1 otherwise. */
    @JvmStatic