code: public static Entry organizationalUnit(String ou, Dn baseDn) {
          Dn dn = LdapUtils.concatDn(SchemaConstants.OU_ATTRIBUTE, ou, baseDn);
          Entry entry = new DefaultEntry(dn);
          try {
              entry.add(SchemaConstants.OBJECT_CLASS_ATTRIBUTE, SchemaConstants.ORGANIZATIONAL_UNIT_OC);
              entry.add(SchemaConstants.OU_ATTRIBUTE, ou);
          } catch (LdapException e) {
              throw new LdapRuntimeException(e);
          }
          return entry;
      }
docs: Returns an {@link Entry} whose {@link Dn} is baseDn followed by ou as Rdn. The attribute type of the Rdn is
  'organizational unit'.