@Override
    public Set<Group> getGroups() {
        Set<Group> result = new HashSet<>();
        for (String groupName : getKnownGroupNamesInList()) {
            result.add(Group.resolveFrom(groupName));
        }
        return result;
    }
Returns the groups that are implied (resolvable) from the items in the list.

@return A Set containing the groups in the list
xmppserver/src/main/java/org/jivesoftware/openfire/group/ConcurrentGroupList.java