code: public static String getString(final LdapEntry entry, final String attribute, final String nullValue) {
          val attr = entry.getAttribute(attribute);
          if (attr == null) {
              return nullValue;
          }
  
          val v = attr.isBinary()
              ? new String(attr.getBinaryValue(), StandardCharsets.UTF_8)
              : attr.getStringValue();
  
          if (StringUtils.isNotBlank(v)) {
              return v;
          }
          return nullValue;
      }
docs: Reads a String value from the LdapEntry.
  
  @param entry     the ldap entry
  @param attribute the attribute name
  @param nullValue the value which should be returning in case of a null value
  @return the string