@Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        final UserInfo userRef = (UserInfo) o;
        return Objects.equals(uuid, userRef.uuid);
    }
@return "Group" or "User" depending on type.
stroom-util-shared/src/main/java/stroom/util/shared/UserInfo.java