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.

    /**
     * Specifies the default value of the configuration property.
     *
     * @return the default value as a string, defaults to empty string
     */
    String defaultValue() default "";

    /**
     * Specifies whether the configuration property is read-only.
     *
     * @return true if the property is read-only, false otherwise
     */
    boolean readOnly() default false;

    @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

    }

    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) {

  )
  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,
  )

        properties.load(new StringReader(TEST_PROPERTIES));

        String test = properties.getProperty("test");
        assertEquals("test", test);

        String defaultValue = properties.getProperty("notfound", "default");
        assertEquals("default", defaultValue);

        properties.setProperty("another", "another");
        Object o1 = properties.getProperty("another");
        assertEquals("another", o1);

    // 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());

     *
     * @param key the property key.
     * @param defaultValue a default value.
     * @return The property value of the default value
     */
    public String getProperty(String key, String defaultValue) {
        if (this.get(key) != null) {
            return this.get(key);
        }
        return defaultValue;
    }

    @Override
    public Set<Entry<String, String>> entrySet() {

     *
     * @param key the property key.
     * @param defaultValue a default value.
     * @return The property value of the default value
     */
    public String getProperty(String key, String defaultValue) {
        if (this.get(key) != null) {
            return this.get(key);
        }
        return defaultValue;
    }

    @Override
    public Set<Entry<String, String>> entrySet() {

     * @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);
    }

    /**