core/src/main/java/com/twitter/elephantbird/util/HadoopUtils.java
@SuppressWarnings("unchecked")
  public static List<String> readStringListFromConfAsJson(String key, Configuration conf) {
    String json = conf.get(key);
    if (json == null) {
      return null;
    }
    return Lists.<String>newArrayList(((JSONArray) JSONValue.parse(json)));
  }
@SuppressWarnings("unchecked")
  public static List<String> readStringListFromConfAsJson(String key, Configuration conf) {
    String json = conf.get(key);
    if (json == null) {
      return null;
    }
    return Lists.<String>newArrayList(((JSONArray) JSONValue.parse(json)));
  }
Reads a list of strings stored as a json array from  a configuration

@param key for the configuration
@param conf to read from
@return the read list of strings, or null if key is not present in conf