I use CalenderUtil for this.i tried few times with my code.but it didn't work.starting date given by date chooser and after the addition of 30 days it need to be set ending date to the other date chooser.but doesn't work and please mention any event i need to prefer. ex: mouseclicked event
import com.google.gwt.user.datepicker.client.CalendarUtil;
import java.text.DateFormat;
import java.util.Date;
Date d;
d = startingdatebox.getDate();
CalendarUtil.addMonthsToDate(d, 1);
endingdatebox.setDate(d);