name     string
		metadata map[string]string
		keys     []string
		want     map[string]string
	}{
		{
			name:     "1",
			metadata: map[string]string{"content-type": "application/octet-stream", "etag": "de75a98baf2c6aef435b57dd0fc33c86", "x-amz-storage-class": "STANDARD", "md5": "abcde"},
			keys:     []string{"etag", "md5"},
			want:     map[string]string{"content-type": "application/octet-stream", "x-amz-storage-class": "STANDARD"},

    public static class ApiSystemInfoResponse extends ApiResponse {
        protected List<Map<String, String>> envProps;
        protected List<Map<String, String>> systemProps;
        protected List<Map<String, String>> fessProps;
        protected List<Map<String, String>> bugReportProps;

        public ApiSystemInfoResponse envProps(final List<Map<String, String>> envProps) {
            this.envProps = envProps;
            return this;

    EntryTransformer<String, Integer, String> transformer =
        new EntryTransformer<String, Integer, String>() {
          @Override
          public String transformEntry(String key, Integer value) {
            return key + value;
          }
        };
    ListMultimap<String, String> transformed = Multimaps.transformEntries(multimap, transformer);

    protected static final String LOCATION_HEADER = "Location";

    @Resource
    protected CrawlerContainer crawlerContainer;

    protected Map<String, String> featureMap = new HashMap<>();

    protected Map<String, String> propertyMap = new HashMap<>();

    protected Map<String, String> childUrlRuleMap = new LinkedHashMap<>();

    protected String defaultEncoding;

            String fieldName,
            ModelProblemCollector problems,
            Severity severity,
            Version version,
            String string,
            String sourceHint,
            InputLocationTracker tracker) {
        if (string == null || string.isEmpty()) {
            return true;
        }

        if ("true".equalsIgnoreCase(string) || "false".equalsIgnoreCase(string)) {

   */
  static String nullToEmpty(@CheckForNull String string) {
    return (string == null) ? "" : string;
  }

  /**
   * Returns the string if it is not empty, or a null string otherwise.
   *
   * @param string the string to test and possibly return
   * @return {@code string} if it is not empty; {@code null} otherwise
   */
  @CheckForNull
  static String emptyToNull(@CheckForNull String string) {

        fun foo() {}

        val bar: String = "bar"

        val bool: Boolean = true

        val isBool: Boolean = true

        var bazar = "bazar"

        var bazool: Boolean = true

        var isFool: Boolean = true

        fun String.fooExt() {}

        fun Int.fooExt() {}

        val String.barExt: String
            get() = "bar"

        var Int.bazarExt: String

    }

    private Map<String, String[]> getResultDocIdsCache(final HttpSession session) {
        @SuppressWarnings("unchecked")
        Map<String, String[]> resultDocIdsCache = (Map<String, String[]>) session.getAttribute(Constants.RESULT_DOC_ID_CACHE);
        if (resultDocIdsCache == null) {
            resultDocIdsCache = new LruHashMap<>(resultDocIdsCacheSize);

     * @throws GeneralSecurityException
     */
    private static void verifyAESMAC ( int usage, String expect, String data, String key ) throws GeneralSecurityException {
        verifyAESHMAC(usage, expect, key, Hex.decode(data));
    }


    private static void verifyArcfourHMAC ( int usage, String expect, String data, String key ) throws GeneralSecurityException {
        verifyArcfourHMAC(usage, expect, key, Hex.decode(data));

    private List<String> activeProfileIds = Collections.emptyList();

    private List<String> inactiveProfileIds = Collections.emptyList();

    private Map<String, String> systemProperties = Collections.emptyMap();

    private Map<String, String> userProperties = Collections.emptyMap();

    private Map<String, String> projectProperties = Collections.emptyMap();