docs: public static Object setJ2CThreadIdentity(Subject subject) throws ThreadIdentityException {
          LinkedHashMap<J2CIdentityService, Object> token = null;
          for (J2CIdentityService j2cIdentityService : j2cIdentityServices) {
              if (j2cIdentityService.isJ2CThreadIdentityEnabled()) {
                  try {
                      Object tokenReturnedFromSet = j2cIdentityService.set(subject);
                      if (tokenReturnedFromSet != null) {
                          if (token == null) {
                              token = new LinkedHashMap<J2CIdentityService, Object>();
                          }
                          token.put(j2cIdentityService, tokenReturnedFromSet);
                      }
                  } catch (Exception e) {
                      com.ibm.ws.ffdc.FFDCFilter.processException(e, thisClass, "272");
                      resetCheckedInternal(token, e);
                  }
              }
          }
          return token;
      }