Primefaces Calender Date comparison only works within the same month - date

Question

I have two calendars. It shouldn´t be possible for the user to pick a date in calendar two that is before the date in calendar one. Also if calender one picks a value that is after calendar two, calender two should change automatically to the same date as calendar one.
This is the index.html. "vom" is Calendar one and "bis" is calendar two.
<p:calendar id="vom" value="#{IndexBean.vom}" maxlength="50"
navigator="true" pattern="dd.mm.yyyy" locale="de" mask="true" >
<f:ajax event="dateSelect" execute="vom" listener="#{IndexBean.dateChanger}" render="vom bis" />
</p:calendar>
<p:calendar id="bis" value="#{IndexBean.bis}" maxlength="50"
navigator="true" pattern="dd.mm.yyyy" locale="de" mask="true" mindate="#{IndexBean.vom}">
<f:ajax event="dateSelect" execute="bis" listener="#{IndexBean.dateChanger}" render="vom bis"/>
</p:calendar>
This is the dateChanger method
public void dateChanger() {
try {
if (bis.before(vom)) {
bis = (Date) vom.clone();
}
} catch (Exception e) {
}
}
The problem is everything works fine as long both calendars are in the same month. I debugged the dateChanger and I´m realy confused about the values coming from the calendars. It doesn´t seem to be dependent of the browser. The type of the dates is java.util.date.
Any clue why this happens?
Java 1.8
JSF 2.2.14

Answer 1

You use a wrong pattern. In
pattern="dd.mm.yyyy"
the mm means 'minutes' and not 'month'. Month is 'MM' so change it to
pattern="dd.MM.yyyy"