Contador de dias corridos

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.Period;
import java.time.format.DateTimeFormatter;
import java.util.Calendar;
import java.util.Date;
import java.util.concurrent.TimeUnit;

import org.junit.Assert;

public class DifferenceBetweenTwoDates {

	public static void main(String[] args) throws ParseException {
		String sFirstDay = "06/24/2017";
		String sSecoundDay = "06/30/2017";

		SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy");
		Date firstDate = sdf.parse(sFirstDay);
		Date secondDate = sdf.parse(sSecoundDay);

		// Sem java 8
		DifferenceBetweenTwoDates ex = new DifferenceBetweenTwoDates();
		Assert.assertEquals(ex.obterDiferencaSemJava8(firstDate, secondDate), 6);
		Assert.assertEquals(ex.obterDiferencaSemJava8APartirSegundoDia(firstDate, secondDate), 5);

		// Com java 8
		DateTimeFormatter dtm = DateTimeFormatter.ofPattern("MM/dd/yyyy");
		LocalDate d1 = LocalDate.parse(sFirstDay, dtm);
		LocalDate d2 = LocalDate.parse(sSecoundDay, dtm);

		Assert.assertEquals(ex.obterDiferencaComJava8(d1, d2), 6);
		Assert.assertEquals(ex.obterDiferencaComJava8APArtirSegundoDia(d1, d2), 5);
	}

	public long obterDiferencaSemJava8(Date firstDate, Date secondDate) {

		long diffInMillies = Math.abs(secondDate.getTime() - firstDate.getTime());
		long diff = TimeUnit.DAYS.convert(diffInMillies, TimeUnit.MILLISECONDS);
		System.out.println(diff);
		return diff;
	}

	public long obterDiferencaSemJava8APartirSegundoDia(Date firstDate, Date secondDate) {

		Calendar c = Calendar.getInstance();
		c.setTime(firstDate);
		c.add(Calendar.DATE, 1);

		return obterDiferencaSemJava8(c.getTime(), secondDate);
	}

	public int obterDiferencaComJava8(LocalDate d1, LocalDate d2) {

		Period period = Period.between(d1, d2);
		int diff = period.getDays();
		System.out.println(diff);
		return diff;

	}

	public int obterDiferencaComJava8APArtirSegundoDia(LocalDate d1, LocalDate d2) {
		d1 = d1.plusDays(1);
		return obterDiferencaComJava8(d1, d2);

	}
}