import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class Main {
	public static void main(String[] args) {
		DateTimeFormatter dtfInput = DateTimeFormatter.ofPattern("dd.MM.uuuu HH:mm z", Locale.ENGLISH);

		ZonedDateTime zdt = ZonedDateTime.from(dtfInput.parse("31.07.2020 14:15 GMT"));
		System.out.println(zdt.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));

		System.out.println(zdt.toInstant());
	}
}