ExecutorService executor = Executors.newSingleThreadExecutor();
    ...
    public synchronized void write(byte[] content, int timeout) throws InterruptedException, SerialPortException{
            long starttime = System.currentTimeMillis();
            Future<Boolean> future = executor.submit(new Callable<Boolean>() {
                public Boolean call() throws Exception {
                    serialPort.writeBytes(content);
                    return new Boolean(true);
                }
            });
            try {
                future.get(timeout, TimeUnit.MILLISECONDS);
                log.debug("Duration: {}",DurationFormatUtils.formatDuration(System.currentTimeMillis() - starttime, "mm:ss.SS"));
            } catch (ExecutionException e) {
                throw new HardwareException(e.getMessage());
            } catch (TimeoutException e) {
                throw new HardwareException("Impossibile scrivere nella porta seriale (timeout)");
            }
        }

public synchronized void write(byte[] content, int timeout) throws InterruptedException, SerialPortException{
        try {
            long starttime = System.currentTimeMillis();
            serialPort.writeBytes(content);
            log.debug("Duration: {}",DurationFormatUtils.formatDuration(System.currentTimeMillis() - starttime, "mm:ss.SS"));
        } catch (SerialPortException e) {
            throw new HardwareException(e.getMessage());
        }
    }