code: @Override
      public String getPortalUserName(final int uPortalUID) {
          final List<String> results =
                  this.jdbcOperations.queryForList(
                          "SELECT USER_NAME FROM UP_USER WHERE USER_ID=?", String.class, uPortalUID);
          return DataAccessUtils.singleResult(results);
      }
docs: /* (non-javadoc)
  @see org.apereo.portal.IUserIdentityStore#getPortalUserName(int)