code: protected final void validateAssertionConditions(final Conditions conditions, final SAML2MessageContext context) {
  
          if (conditions == null) {
              return;
          }
  
          if (conditions.getNotBefore() != null && conditions.getNotBefore().minusSeconds(acceptedSkew).isAfterNow()) {
              throw new SAMLAssertionConditionException("Assertion condition notBefore is not valid");
          }
  
          if (conditions.getNotOnOrAfter() != null && conditions.getNotOnOrAfter().plusSeconds(acceptedSkew).isBeforeNow()) {
              throw new SAMLAssertionConditionException("Assertion condition notOnOrAfter is not valid");
          }
  
          final String entityId = context.getSAMLSelfEntityContext().getEntityId();
          validateAudienceRestrictions(conditions.getAudienceRestrictions(), entityId);
      }
docs: Validate assertionConditions
  - notBefore
  - notOnOrAfter
  
  @param conditions the conditions
  @param context    the context