@Override
    public Group createGroup(String name) throws GroupAlreadyExistsException, GroupNameInvalidException {
        if (isReadOnly()) {
            throw new UnsupportedOperationException("Cannot create groups via read-only provider");
        }
        synchronized (sharedGroupMetaCache) {
            sharedGroupMetaCache.clear();
        }

        return null; // aught to be overridden.
    }
@throws UnsupportedOperationException if the provider is read only
xmppserver/src/main/java/org/jivesoftware/openfire/group/AbstractGroupProvider.java