@Override
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
        groupManager = GroupManager.getInstance();
        provider = groupManager.getProvider();

        name = ExternalizableUtil.getInstance().readSafeUTF(in);
        if (ExternalizableUtil.getInstance().readBoolean(in)) {
            description = ExternalizableUtil.getInstance().readSafeUTF(in);
        }

        final int memberSize = ExternalizableUtil.getInstance().readInt(in);
        final List<JID> tmpMembers = new ArrayList<>(memberSize);
        for (int i = 0; i < memberSize; i++) {
            final JID member = (JID) ExternalizableUtil.getInstance().readSerializable(in);
            tmpMembers.add(member);
        }
        members = new MemberCollection(tmpMembers, false);

        final int administratorSize = ExternalizableUtil.getInstance().readInt(in);
        final List<JID> tmpAdministrators = new ArrayList<>(administratorSize);
        for (int i = 0; i < administratorSize; i++) {
            final JID administrator = (JID) ExternalizableUtil.getInstance().readSerializable(in);
            tmpAdministrators.add(administrator);
        }
        administrators = new MemberCollection(tmpAdministrators, true);
    }
Returns an iterator over the users in this collection.

The returned iterator is <i>weakly consistent</i>.

@return an iterator over the users in this collection
xmppserver/src/main/java/org/jivesoftware/openfire/group/Group.java