@SuppressWarnings("unchecked")
    public List<String> getList(String key) {
        return (List<String>) get(key);
    }
@Test
    public void testEmptyList() {
        AbstractConfig conf;
        ConfigDef configDef = new ConfigDef().define("a", Type.LIST, "", new ConfigDef.NonNullValidator(), Importance.HIGH, "doc");

        conf = new AbstractConfig(configDef, Collections.emptyMap());
        assertEquals(Collections.emptyList(), conf.getList("a"));

        conf = new AbstractConfig(configDef, Collections.singletonMap("a", ""));
        assertEquals(Collections.emptyList(), conf.getList("a"));

        conf = new AbstractConfig(configDef, Collections.singletonMap("a", "b,c,d"));
        assertEquals(Arrays.asList("b", "c", "d"), conf.getList("a"));
    }