class DateUtils {

  public static Date yearStart() {
    final GregorianCalendar calendar = new GregorianCalendar(US);
    calendar.set(DAY_OF_YEAR, 1);
    return calendar.getTime();
  }

}

class DateUtilsTest {

  @Test
  public void yearStart() {

    Date date = DateUtils.yearStart();
    assertNotNull(date);
    GregorianCalendar calendar = new GregorianCalendar();
    calendar.setTime(date);
    assertEquals(1, calendar.get(DAY_OF_YEAR));
  }

}