private List<User> getChildrenOf(final Condition condition,
                                     final Collection<OrderField<?>> orderFields,
                                     final int offset,
                                     final int limit) {
        // Get all direct children of a group
        LOGGER.debug("getChildrenOf - condition: {}", condition);
        final List<User> list;
        list = JooqUtil.contextResult(securityDbConnProvider, context -> context
                        .selectDistinct()
                        .from(STROOM_USER)
                        .join(STROOM_USER_GROUP).on(STROOM_USER_GROUP.USER_UUID.eq(STROOM_USER.UUID))
                        .where(condition)
                        .orderBy(orderFields)
                        .offset(offset)
                        .limit(limit)
                        .fetch())
                .stream()
                .map(RECORD_TO_USER_MAPPER)
                .toList();
        return list;
    }
Get user or group by their UUID.
stroom-security/stroom-security-impl-db/src/main/java/stroom/security/impl/db/UserDaoImpl.java