code: @Override
      public void init(FilterConfig filterConfig) {
          String m = "L init() ";
          try {
              logger.debug(m + ">");
              super.init(filterConfig);
              m = FilterSetup.getFilterNameAbbrev(FILTER_NAME) + " init() ";
              inited = false;
              if (!initErrors) {
                  Set<String> temp = new HashSet<String>();
                  if (ATTRIBUTES2RETURN == null) {
                      ATTRIBUTES2RETURN = EMPTY_STRING_ARRAY;
                  } else {
                      for (String element : ATTRIBUTES2RETURN) {
                          temp.add(element);
                      }
                  }
                  if (AUTHENTICATE && PASSWORD != null && !PASSWORD.isEmpty()) {
                      temp.add(PASSWORD);
                  }
                  DIRECTORY_ATTRIBUTES_NEEDED =
                          (String[]) temp.toArray(StringArrayPrototype);
  
                  boolean haveBindMethod = false;
                  if (SECURITY_AUTHENTICATION != null
                          && !SECURITY_AUTHENTICATION.isEmpty()) {
                      haveBindMethod = true;
                  }
  
                  boolean haveSuperUser = false;
                  if (SECURITY_PRINCIPAL != null
                          && !SECURITY_PRINCIPAL.isEmpty()) {
                      haveSuperUser = true;
                  }
  
                  boolean haveSuperUserPassword = false;
                  if (SECURITY_CREDENTIALS != null
                          && !SECURITY_CREDENTIALS.isEmpty()) {
                      haveSuperUserPassword = true;
                  }
  
                  if (haveBindMethod && haveSuperUserPassword) {
                      initErrors = !haveSuperUser;
                  }
  
              }
              if (initErrors) {
                  logger.error(m + "not initialized; see previous error");
              }
              inited = true;
          } finally {
              logger.debug("{}<", m);
          }
      }
docs: public Boolean REQUIRE_RETURNED_ATTRS = Boolean.FALSE;