Read Scheduler(Fixed-delay) from Database in Spring boot - spring-boot

Question

I'm developing a spring boot project which uses spring batch scheduler to read data after 2 sec's and send it to the message broker (Activemq) which works fine with hardcoded fixed delay.
However, i'm now trying to read the #Scheduled(fixedDelay) from database rather hard coded but looks like nothing is working out. I can see the expression contains 10 secs but scheduler doesn't start
#Service
public class QuoteService implements ApplicationListener<BrokerAvailabilityEvent> {
private static Log logger = LogFactory.getLog(QuoteService.class);
private final MessageSendingOperations<String> messagingTemplate;
private final StockQuoteGenerator quoteGenerator = new StockQuoteGenerator();
private AtomicBoolean brokerAvailable = new AtomicBoolean();
private ReadCronExpressionDataService readCronExpressionDataService;
private int expression;
#Autowired
public QuoteService(MessageSendingOperations<String> messagingTemplate,ReadCronExpressionDataService readCronExpressionDataService) {
this.messagingTemplate = messagingTemplate;
this.readCronExpressionDataService=readCronExpressionDataService;
expression = readCronExpressionDataService.readData();
}
#Scheduled(fixedDelay=expression) //#Scheduled(fixedDelay=2000)
public void sendQuotes() {
for (Quote quote : this.quoteGenerator.generateQuotes()) {
if (logger.isTraceEnabled()) {
logger.trace("Sending quote " + quote);
}
if (this.brokerAvailable.get()) {
this.messagingTemplate.convertAndSend("/topic/price.stock." + quote.getTicker(), quote);
}
}
}
private static class StockQuoteGenerator {
private static final MathContext mathContext = new MathContext(2);
private final Random random = new Random();
private final Map<String, String> prices = new ConcurrentHashMap<>();
public StockQuoteGenerator() {
this.prices.put("CTXS", "24.30");
this.prices.put("DELL", "13.03");
this.prices.put("EMC", "24.13");
this.prices.put("GOOG", "893.49");
this.prices.put("MSFT", "34.21");
this.prices.put("ORCL", "31.22");
this.prices.put("RHT", "48.30");
this.prices.put("VMW", "66.98");
}
public Set<Quote> generateQuotes() {
Set<Quote> quotes = new HashSet<>();
for (String ticker : this.prices.keySet()) {
BigDecimal price = getPrice(ticker);
quotes.add(new Quote(ticker, price));
}
return quotes;
}
private BigDecimal getPrice(String ticker) {
BigDecimal seedPrice = new BigDecimal(this.prices.get(ticker), mathContext);
double range = seedPrice.multiply(new BigDecimal(0.02)).doubleValue();
BigDecimal priceChange = new BigDecimal(String.valueOf(this.random.nextDouble() * range), mathContext);
return seedPrice.add(priceChange);
}
}
}
Any idea?