code: protected void verifyTimestamp(WSHandlerResult result) throws WSSecurityException {
          List<WSSecurityEngineResult> insertTimestampResults = result.getActionResults().getOrDefault(WSConstants.TS, emptyList());
          if (insertTimestampResults.isEmpty()) {
              throw new Wss4jSecurityValidationException("No action results for 'Insert timestamp' found");
          } else if (insertTimestampResults.size() > 1) {
              throw new Wss4jSecurityValidationException("Multiple action results for 'Insert timestamp' found. Expected only 1.");
          }
          WSSecurityEngineResult actionResult = insertTimestampResults.get(0);
  
          if (actionResult != null) {
              Timestamp timestamp = (Timestamp) actionResult.get(WSSecurityEngineResult.TAG_TIMESTAMP);
              if (timestamp != null && timestampStrict) {
                  Credential credential = new Credential();
                  credential.setTimestamp(timestamp);
  
                  RequestData requestData = new RequestData();
                  requestData.setWssConfig(WSSConfig.getNewInstance());
                  requestData.setTimeStampTTL(validationTimeToLive);
                  requestData.setTimeStampStrict(timestampStrict);
  
                  TimestampValidator validator = new TimestampValidator();
                  validator.validate(credential, requestData);
              }
          }
      }
docs: Verifies the timestamp.