archaius-core/src/main/java/com/netflix/config/ConcurrentCompositeConfiguration.java
private static void appendListProperty(List<Object> dest, Configuration config,
            String key)
    {
        Object value = config.getProperty(key);
        if (value != null)
        {
            if (value instanceof Collection)
            {
                Collection<?> col = (Collection<?>) value;
                dest.addAll(col);
            }
            else
            {
                dest.add(value);
            }
        }
    }
private static void appendListProperty(List<Object> dest, Configuration config,
            String key)
    {
        Object value = config.getProperty(key);
        if (value != null)
        {
            if (value instanceof Collection)
            {
                Collection<?> col = (Collection<?>) value;
                dest.addAll(col);
            }
            else
            {
                dest.add(value);
            }
        }
    }
Adds the value of a property to the given list. This method is used by
{@code getList()} for gathering property values from the child
configurations.

@param dest the list for collecting the data
@param config the configuration to query
@param key the key of the property