proceeded year calendar

src/main/java/de/kreth/vaadin/clubhelper/vaadinclubhelper/ui/components/calendar/Year.java

@@ -46,7 +46,12 @@ public class Year {
 	 * @return	numeric value of the day of the month.
 	 */
 	public String getDay(Month month, short week, DayOfWeek dayOfWeek) {
-		Integer res = monthWeeks.get(month).getWeek(week - 1).get(dayOfWeek);
+		
+		WeeksOfMonth weeksOfMonth = monthWeeks.get(month);
+		if (week >= weeksOfMonth.weekCount()) {
+			return "";
+		}
+		Integer res = weeksOfMonth.getWeek(week - 1).get(dayOfWeek);
 		
 		return res == null ?  "" : res.toString();
 				

src/test/java/de/kreth/vaadin/clubhelper/vaadinclubhelper/ui/components/calendar/WeeksOfMonthTest.java

@@ -12,6 +12,15 @@ import org.junit.jupiter.api.Test;
 
 class WeeksOfMonthTest {
 
+	@Test
+	void test2018January() {
+		WeeksOfMonth january = new WeeksOfMonth(Month.JANUARY, 2018);
+		assertEquals(31, january.dayCount());
+		assertEquals(5, january.weekCount());
+		assertEquals(1, january.getWeek(0).get(DayOfWeek.MONDAY).intValue());
+		assertEquals(31, january.getWeek(4).get(DayOfWeek.WEDNESDAY).intValue());
+	}
+	
 	@Test
 	void test2018November() {
 		WeeksOfMonth november = new WeeksOfMonth(Month.NOVEMBER, 2018);