Get Number of Days of one month and year JAVA

Question

I have a date, I want to get the number of days of one month of one year for example:

GregorianCalendar calendar = new GregorianCalendar();
calendar.setTime(date);

let's assume this date is 04/14/2014, then I would get the number of day of the month 04 In our case is 30 days, how do it ?

thanks