public static Configuration resolve(Configuration conf) {
    Configuration resolved = new Configuration(false);
    for (Map.Entry<String, String> entry : conf) {
      resolved.set(entry.getKey(), conf.get(entry.getKey()));
    }
    return resolved;
  }
@Test
  public void resolve() {
    Configuration conf = new Configuration(false);
    conf.set("a", "A");
    conf.set("b", "${a}");
    assertEquals(conf.getRaw("a"), "A");
    assertEquals(conf.getRaw("b"), "${a}");
    conf = ConfigurationUtils.resolve(conf);
    assertEquals(conf.getRaw("a"), "A");
    assertEquals(conf.getRaw("b"), "A");
  }