for(String m_clans : plugin.getClans() ){
    // for each property in the static list above
    plugin.log.info("Writing for " + m_clans);
    for(String prop : CLAN_DEFAULTS.keySet()){
        plugin.log.info("Writing for " + prop);
        if (clans.getProperty("clans." + m_clans + prop) == null) {
            clans.setProperty("clans." + m_clans + prop, CLAN_DEFAULTS.get("clans." + m_clans + prop));
                    }
                }
            }