public static Collection<String> getStringCollection(Configuration conf, ConfVars var) {
    assert var.defaultVal.getClass() == String.class;
    String val = conf.get(var.varname);
    if (val == null) {
      val = conf.get(var.hiveName, (String)var.defaultVal);
    }
    if (val == null) {
      return Collections.emptySet();
    }
    return StringUtils.asSet(val.split(","));
  }
Treat a configuration value as a comma separated list.
@param conf configuration to retrieve it from
@param var variable to retrieve
@return collection of strings.  If the value is unset it will return an empty collection.
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/conf/MetastoreConf.java