public PrivacyList getDefaultPrivacyList(String username) {
        // Check if we have the default list in the cache
        final String cacheKey = getDefaultCacheKey(username);
        final Lock lock = listsCache.getLock(cacheKey);
        lock.lock();
        try {
            PrivacyList list = listsCache.get(cacheKey);
            if (list == null) {
                // Load default list from the database
                list = provider.loadDefaultPrivacyList(username);
                if (list != null) {
                    listsCache.put(cacheKey, list);
                }
            }
            return list;
        } finally {
            lock.unlock();
        }
    }
Returns the default privacy list of the specified user or {@code null} if
none was found.

@param username the name of the user to get his default list.
@return the default privacy list of the specified user or {@code null} if
        none was found.
xmppserver/src/main/java/org/jivesoftware/openfire/privacy/PrivacyListManager.java