import java.time.*;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
 
public class Main {
    private static final DateTimeFormatter FORMATTER =
            DateTimeFormatter.ofPattern("dd/MM/uuuu", Locale.ENGLISH);
 
    public static void main(String[] args) {
        // Test
        ZonedDateTime zdt = convertTimeZone("23/04/2013", "23:00",
                ZoneId.of("America/New_York"), // source time zone
                ZoneId.of("Europe/London")); // target time zone
        System.out.println(zdt);
 
        // In custom format
        System.out.println(zdt.format(FORMATTER) + " " + zdt.toLocalTime());
    }
 
    private static ZonedDateTime convertTimeZone(String strDate, String strTime, ZoneId sourceTz, ZoneId targetTz) {
 
        LocalDate date = LocalDate.parse(strDate, FORMATTER);
        LocalTime time = LocalTime.parse(strTime);
        ZonedDateTime zdt = ZonedDateTime.of(date, time, sourceTz);
        return zdt.withZoneSameInstant(targetTz);
    }
}

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