public Set<JID> getBlockedJIDs()
    {
        final Set<JID> result = new HashSet<>();

        for ( final PrivacyItem item : items )
        {
            if ( !item.isAllow() && item.isType( PrivacyItem.Type.jid ) )
            {
                if ( item.getJID() != null )
                {
                    result.add( item.getJID() );
                }
            }
        }

        return result;
    }
Returns all JIDs that are on the blocklist (as defined in XEP-0191).

@return a collection of JIDs (possibly empty, never null)
xmppserver/src/main/java/org/jivesoftware/openfire/privacy/PrivacyList.java