Java Time4J – Getting Started

 // conversion from jalali to gregorian by constructed input
PersianCalendar jalali = PersianCalendar.of(1394, 11, 5);
// or use a safe enum instead of the month number:
// PersianCalendar jalali = PersianCalendar.of(1394, PersianMonth.BAHMAN, 5);

PlainDate gregorian = jalali.transform(PlainDate.class); 
System.out.println(gregorian); // 2016-01-25;

PersianCalendar persianCalendar= plainDate2.transform(PersianCalendar.class);

References :
http://stackoverflow.com/questions/23385434/a-good-date-converter-for-jalali-calendar-in-java