I wrote some simple code, found some problems, took the day's opening price, and the closing price was different from by the platform displayed:
Please tell me what the reason is
Examples are as follows:

public class GetBarsExample implements IStrategy {
@Configurable("Instrument")
public Instrument Curinstrument = Instrument.AUDJPY;

private IContext context;
private IConsole console;
private IHistory history;
private IBar prevDailyBar;
private SimpleDateFormat gmtSdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

public void onStart(IContext context) throws JFException {
this.context = context;
console = context.getConsole();
history = context.getHistory();

context.setSubscribedInstruments(java.util.Collections.singleton(Instrument.EURUSD), true);
//today BARS
prevDailyBar = history.getBar(Curinstrument, Period.DAILY, OfferSide.ASK, 0);

console.getInfo().format(" today open price=%.5f ", prevDailyBar .getOpen()).println();

console.getInfo().format(" today time=%s open price=%.5f close price=%.5f ",gmtSdf.format(prevDailyBar.getTime()),prevDailyBar .getOpen(), prevDailyBar .getClose()).println();
}
console printinfo:
today time=2018-04-17 08:00:00 open price=83.24000 close price=83.21800

but he platform displayed:
4-17 (aud/jpy today open price is 83.312

Hello.
history.getBar() gets bars using GMT Timezone. Platform displays prices depending on your chart Timezone settings. You can check it in:
Settings - Preferences - Chart - Day Start Time.
If you will switch it to GMT, price from history.getBar() and in OHLC widget will be identical.

oh,i see.thanks.

There is also a question of how to take the opening price in different time zones？？？

You can implement some custom method, pass timezone and date to it and use SimpleDateFormat as a timezone switcher.
Example:

@Configurable("TimeZone")
 public String timezoneAsString;

    @Override
    public void onBar(Instrument instrument, Period period, IBar askBar, IBar bidBar) throws JFException {
        if (Curinstrument != instrument || this.period != period) {
            return;
        }

        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(askBar.getTime());

        IBar barByTimeZone = getBarByTimeZone(timezoneAsString, calendar);

        console.getInfo().format(" %s, today time=%s open price=%.5f close price=%.5f ", timezoneAsString, dateFormat.format(barByTimeZone.getTime()),
                barByTimeZone.getOpen(), barByTimeZone.getClose()).println();
    }

    private IBar getBarByTimeZone(String timezoneAsString, Calendar date) {
        long barTime = 0;

        try {
            dateFormat.setTimeZone(TimeZone.getTimeZone(timezoneAsString));
            Date dateFrom = dateFormat.parse(sdf.format(date.getTime()));
            barTime = dateFrom.getTime();
        } catch (Exception e) {
            console.getErr().println(e.getMessage());
        }

        if (barTime != 0) {
            try {
                List<IBar> barsByTime = history.getBars(Curinstrument, period, OfferSide.ASK, barTime , barTime);
                if (barsByTime.size() <= 1) {
                    return barsByTime.get(0);
                }

            } catch (Exception exc) {
                console.getErr().println(exc.getMessage());
            }
        }

        return null;
    }