class HadoopConfigurationProperty {

  public Collection<String> getStringCollection(Configuration config) {
    checkState(
        defaultValue == null || defaultValue instanceof Collection, "Not a collection property");
    String lookupKey = getLookupKey(config, key, deprecatedKeys, (c, k) -> c.get(k) != null);
    String valueString =
        config.get(
            lookupKey,
            defaultValue == null ? null : COMMA_JOINER.join((Collection<?>) defaultValue));
    List<String> value = COMMA_SPLITTER.splitToList(nullToEmpty(valueString));
    return logProperty(lookupKey, value);
  }

  public  HadoopConfigurationProperty(String key);
  public  HadoopConfigurationProperty(String key, T defaultValue, String... deprecatedKeys);

}