With Java 8's date time API change, Use LocalDate
LocalDate date = LocalDate.now().minusDays(300);
Similarly you can have
LocalDate date = someLocalDateInstance.minusDays(300);
Refer to https://stackoverflow.com/a/23885950/260990 for translation between java.util.Date <--> java.time.LocalDateTime
Date in = new Date();
LocalDateTime ldt = LocalDateTime.ofInstant(in.toInstant(), ZoneId.systemDefault());
Date out = Date.from(ldt.atZone(ZoneId.systemDefault()).toInstant());
Calendar cal = Calendar.getInstance();
cal.setTime(dateInstance);
cal.add(Calendar.DATE, -30);
Date dateBefore30Days = cal.getTime();