Calendar Class In Java. Calendar class in java is an abstract class that provides methods for converting date between a specific instant in time and a set of calendar fields such as month, year,. The java.util.calendar class is an abstract class and you obtain the instance of a calendar local to your timezone and locale by calling the getinstance() method of java.util.calendar class.

Calculating the difference between two dates; Another important enhancement of the calendar class is its calendar.era constant: