throw new UnsupportedOperationException();
  }

  private <T> T pickInstance(T[] instances, T defaultValue) {
    return pickInstance(Arrays.asList(instances), defaultValue);
  }

  private <T> T pickInstance(Collection<T> instances, T defaultValue) {
    if (instances.isEmpty()) {
      return defaultValue;
    }
    // generateInt() is 1-based.

    }

    default String getSystemProperty(final String key, final String defaultValue) {
        return ComponentUtil.getSystemProperties().getProperty(key, System.getProperty(Constants.SYSTEM_PROP_PREFIX + key, defaultValue));
    }

    default void setSystemProperty(final String key, final String value) {
        if (value != null) {

    @Override
    public Object get(final Object key) {
        return getProperties().get(key);
    }

    @Override
    public String getProperty(final String key, final String defaultValue) {
        return getProperties().getProperty(key, defaultValue);
    }

    @Override
    public String getProperty(final String key) {
        return getProperties().getProperty(key);
    }

    @Override

  )
  fun handshake(): Handshake? = handshake

  fun headers(name: String): List<String> = headers.values(name)

  @JvmOverloads
  fun header(
    name: String,
    defaultValue: String? = null,
  ): String? = headers[name] ?: defaultValue

  @JvmName("-deprecated_headers")
  @Deprecated(
    message = "moved to val",
    replaceWith = ReplaceWith(expression = "headers"),
    level = DeprecationLevel.ERROR,
  )

    /*
     * Even though it's weird to pass a defaultValue that is null, some callers do so. Those who
     * pass a literal "null" should probably just use `get`, but I would expect other callers to
     * pass an expression that *might* be null. This could happen with:
     *
     * - a `getFooOrDefault(@Nullable Foo defaultValue)` method that returns

     * @param key the key to look up
     * @param defaultValue the default value to return if key is not found or value is blank
     * @return the value from the map or the default value
     */
    private String getValueFromMap(final Map<String, String> dataMap, final String key, final String defaultValue) {
        final String value = dataMap.get(key);
        if (StringUtil.isBlank(value)) {

     * @param key the parameter key to look up
     * @param defaultValue the default value to return if key is not found
     * @return the parameter value as a string, or the default value if not found
     */
    protected String getParamValue(final DataStoreParams paramMap, final String key, final String defaultValue) {
        return paramMap.getAsString(key, defaultValue);
    }

    /**

    // We assume that all defaults are generics-safe, even if they aren't,
    // we take the risk.
    @SuppressWarnings("unchecked")
    T defaultValue = (T) defaults.getInstance(type.getRawType());
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe
    T arbitrary = (T) ArbitraryInstances.get(type.getRawType());

        }

        // Expose protected methods for testing
        public void testAddSystemProperty(List<String> cmdList, String name, String defaultValue, String appendValue) {
            super.addSystemProperty(cmdList, name, defaultValue, appendValue);
        }

        public void testAddFessConfigProperties(List<String> cmdList) {
            super.addFessConfigProperties(cmdList);
        }

		} else {
			tests.AssertObjEqual(t, parsedField, f, "Name", "DBName", "BindNames", "DataType", "PrimaryKey", "AutoIncrement", "Creatable", "Updatable", "Readable", "HasDefaultValue", "DefaultValue", "NotNull", "Unique", "Comment", "Size", "Precision", "TagSettings")

			if f.DBName != "" {
				if field, ok := s.FieldsByDBName[f.DBName]; !ok || parsedField != field {