checkArgument(type != implementation, "Don't register %s to itself!", type);
    checkArgument(
        !DEFAULTS.containsKey(type), "A default value was already registered for %s", type);
    checkArgument(
        implementations.put(type, implementation) == null,
        "Implementation for %s was already registered",
        type);
  }

  static {
    setImplementation(Appendable.class, StringBuilder.class);

    checkArgument(type != implementation, "Don't register %s to itself!", type);
    checkArgument(
        !DEFAULTS.containsKey(type), "A default value was already registered for %s", type);
    checkArgument(
        implementations.put(type, implementation) == null,
        "Implementation for %s was already registered",
        type);
  }

  static {
    setImplementation(Appendable.class, StringBuilder.class);

    private final Logger logger = LoggerFactory.getLogger(getClass());

    private final MessageBuilderFactory messageBuilderFactory;

    /**
     * Default ctor is used in IT and most probably some 3rd party code. For those cases, we do provide sane defaults
     * but given this is a component, injection should be used, replacing direct instantiation.
     *

 * <th>Alphabet
 * <th>{@code char:byte} ratio
 * <th>Default padding
 * <th>Comments
 * <tr>
 * <td>{@link #base16()}
 * <td>0-9 A-F
 * <td>2.00
 * <td>N/A
 * <td>Traditional hexadecimal. Defaults to upper case.
 * <tr>
 * <td>{@link #base32()}
 * <td>A-Z 2-7
 * <td>1.60
 * <td>=
 * <td>Human-readable; no possibility of mixing up 0/O or 1/I. Defaults to upper case.
 * <tr>
 * <td>{@link #base32Hex()}

        Object transport = mergedProps.getOrDefault(MAVEN_RESOLVER_TRANSPORT_KEY, MAVEN_RESOLVER_TRANSPORT_DEFAULT);
        if (MAVEN_RESOLVER_TRANSPORT_DEFAULT.equals(transport)) {
            // The "default" mode (user did not set anything) from now on defaults to AUTO
        } else if (MAVEN_RESOLVER_TRANSPORT_JDK.equals(transport)) {

    // Test loading system properties
    result = Maps.fromProperties(System.getProperties());
    assertTrue(result.containsKey("java.version"));

    // Test that defaults work, too.
    testProp = new Properties(System.getProperties());
    String override = "test\njava.version : hidden";

    testProp.load(new StringReader(override));

    // Test loading system properties
    result = Maps.fromProperties(System.getProperties());
    assertTrue(result.containsKey("java.version"));

    // Test that defaults work, too.
    testProp = new Properties(System.getProperties());
    String override = "test\njava.version : hidden";

    testProp.load(new StringReader(override));

public final class CacheBuilder<K, V> {
  private static final int DEFAULT_INITIAL_CAPACITY = 16;
  private static final int DEFAULT_CONCURRENCY_LEVEL = 4;

  @SuppressWarnings("GoodTime") // should be a java.time.Duration
  private static final int DEFAULT_EXPIRATION_NANOS = 0;

  @SuppressWarnings("GoodTime") // should be a java.time.Duration
  private static final int DEFAULT_REFRESH_NANOS = 0;

    public static final String DEFAULT_FESS_URL = "http://localhost:8080";
    public static final String DEFAULT_SEARCH_ENGINE_URL = "http://localhost:9200";
    public static final String DEFAULT_TEST_TOKEN = "E44TjYrJQadtGBFFuECA0SBqqVtqj7lRGmhYep53ixNdvlRxnkhwqCVCpRoO";
    public static final String DEFAULT_TEST_TOKEN_ID = "testToken";
    private static final String TEST_TOKEN = "test.token";

                wConfig.setExcludedDocUrls(getDefaultString("default.config.web.excludedDocUrls", StringUtil.EMPTY));
                wConfig.setExcludedUrls(getDefaultString("default.config.web.excludedUrls", StringUtil.EMPTY));
                wConfig.setIncludedDocUrls(getDefaultString("default.config.web.includedDocUrls", StringUtil.EMPTY));
                wConfig.setIncludedUrls(getDefaultString("default.config.web.includedUrls", StringUtil.EMPTY));