import java.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class Main {
	public static void main(String[] args) {
		// Test
		System.out.println(getFormattedDateTimeInDeviceTz("2021-10-26T18:12:20.698134Z", "uuuu-MM-dd'T'HH:mm:ssXXX"));
	}

	static String getFormattedDateTimeInDeviceTz(String iso, String pattern) {
		Instant instant = Instant.parse(iso);

		// Get the date-time in the device's timezone (e.g. Asia/Kolkata
		DateTimeFormatter dtf = DateTimeFormatter.ofPattern(pattern, Locale.ENGLISH);
		return instant.atZone(ZoneId.of("Asia/Kolkata")).format(dtf);
	}
}