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Calendar Class in Java

Last Updated: 06 March, 2023

The Calendar is an abstract class that provides methods for converting dates between a specific instant in time and a set of calendar fields such as YEAR, MONTH, DAY_OF_MONTH, HOUR, etc. The Calendar class is available in the java.util package.

Calender is an abstract class, so we cannot create an object; we can use the static method Calendar.getInstance() to instantiate and implement a sub-class.

The getInstance() method returns a Calendar instance based on the current time in the default time zone with the default locale.

Java Calendar Class Example Program

  
  import java.util.Calendar;
  public class CalendarExample {
    public static void main(String args[]) {
      Calendar cal = Calendar.getInstance();
      System.out.println("Current Date and time: " + cal.getTime());
    }
  }

Output

Current Date and time: Sun Feb 05 18:15:22 IST 2023

Calendar class declaration:

 public abstract class Calendar extends Object implements Serializable, Cloneable, Comparable<Calendar>

The abstract Calendar class extends Object class and implements Serializable, Cloneable, and Comparable interfaces in Java.

Constructors of the Java Calendar class

No.	Constructors and Description
1	protected Calendar() It is used to construct a Calendar with the default time zone and locale.
2	protected Calendar(TimeZone zone, Locale aLocale) It is used to construct a calendar with the specified time zone and locale.

Methods of the Java Calendar class

No.	Methods and Description
1	Calendar getInstance() It returns a calendar using the default time zone and locale.
2	Date getTime() It returns a Date object representing the invoking Calendar's time value.
3	TimeZone getTimeZone() It returns the time zone object associated with the invoking calendar.
4	String getCalendarType() It returns an instance of the Date object from an instant date.
5	int get(int field) It returns the value for the given calendar field.
6	int getFirstDayOfWeek() It returns the day of the week in integer form.
7	int getWeeksInWeekYear() It reruns the total number of weeks in a year.
8	int getWeekYear() It returns the week and year represented by the current calendar.
9	void add(int field, int amount) It adds the specified amount of time to the given calendar field.
10	boolean after (Object when) It returns true if the time represented by the Calendar is after the time represented by the object.
11	boolean before(Object when) It returns true if the time represented by the Calendar is before the time represented by when Object.
12	void clear(int field) It sets the given calendar field value and the time value of this Calendar undefined.
13	Object clone() It makes a copy of the current object.
14	int compareTo(Calendar anotherCalendar) It compares and retruns the time values (millisecond offsets) between two calendar objects.
15	void complete() It sets any unset fields in the calendar fields.
16	void computeFields() It converts the current millisecond time value time to calendar field values in fields[].
17	void computeTime() It converts the current calendar field values in fields[] to the millisecond time value time.
18	boolean equals(Object object) It returns true if both the invoking object and the argumented object are equal.
19	int getActualMaximum(int field) It returns the maximum possible value of the specified calendar field.
20	int getActualMinimum(int field) It returns the minimum possible value of the specified calendar field.
21	Set getAvailableCalendarTypes() It returns a string set of all available calendar types supported by the Java Runtime Environment.
22	Locale[] getAvailableLocales() It returns an array of all locales available in Java runtime environment.
23	String getDisplayName(int field, int style, Locale locale) It returns the String representation of the specified calendar field value in a given style and locale.
24	Map getDisplayNames(int field, int style, Locale locale) It returns a Map representation of the given calendar field value in a given style and locale.
25	int getGreatestMinimum(int field) It returns the highest minimum value of the specified Calendar field.
26	int getLeastMaximum(int field) It returns the highest maximum value of the specified Calendar field.
27	int getMaximum(int field) It returns the maximum value of the specified calendar field.
28	int getMinimalDaysInFirstWeek() It returns the required minimum days in integer form.
29	int getMinimum(int field) It returns the minimum value of the specified calendar field.
30	long getTimeInMillis() It returns the current time in milliseconds.
31	int hashCode() It returns the hash code of the invoking object.
32	int internalGet(int field) It returns the value of the given calendar field.
33	boolean isLenient() It returns true if the interpretation mode of this calendar is lenient; false otherwise.
34	boolean isSet(int field) If the value is not set, it returns false; otherwise, it returns true.
35	boolean isWeekDateSupported() It returns true if the calendar supports the specified week date. The default value is false.
36	void roll(int field, boolean up) It increases or decreases the specified calendar field by one unit without affecting the other field.
37	void set(int field, int value) It sets the specified calendar field to the specified value.
38	void setFirstDayOfWeek(int value) It sets the first day of the week.
39	void setMinimalDaysInFirstWeek(int value) It sets the minimal days required in the first week.
40	void setTime(Date date) It sets the Time of current calendar object.
41	void setTimeInMillis(long millis) It sets the current time in milliseconds.
42	void setTimeZone(TimeZone value) It sets the TimeZone with passed TimeZone value.
43	void setWeekDate(int weekYear, int weekOfYear, int dayOfWeek) It sets the current date with specified integer value.
44	Instant toInstant() It converts the current object to an instant.
45	String toString() It returns a string representation of the current object.

Example 1: Calendar class add() and getInstance() methods

  
  import java.util.Calendar;
  public class CalendarExample1 {
    public static void main(String[] args) {
      Calendar calendar = Calendar.getInstance();
      
      System.out.println("The current date is : " + calendar.getTime());
      
      calendar.add(Calendar.DATE, -15);
      System.out.println("15 days ago: " + calendar.getTime());
      
      calendar.add(Calendar.MONTH, 4);
      System.out.println("4 months later: " + calendar.getTime());
      
      calendar.add(Calendar.YEAR, 2);
      System.out.println("5 years later: " + calendar.getTime());
    }
  }

Output

The current date is : Sun Mar 05 12:28:11 IST 2023
15 days ago: Sat Feb 18 12:28:11 IST 2023
4 months later: Sun Jun 18 12:28:11 IST 2023
5 years later: Wed Jun 18 12:28:11 IST 2025

Example 2: Calendar class get() method

  
  import java.util.Calendar;
  public class CalendarExample2 {
    public static void main(String[] args) {
      Calendar calendar = Calendar.getInstance();
      
      System.out.println("Current Calendar's Year: " + calendar.get(Calendar.YEAR));
      System.out.println("Current Calendar's Day: " + calendar.get(Calendar.DATE));
      System.out.println("Current MINUTE: " + calendar.get(Calendar.MINUTE));
      System.out.println("Current SECOND: " + calendar.get(Calendar.SECOND));
    }
  }

Output

Current Calendar's Year: 2023
Current Calendar's Day: 5
Current MINUTE: 30
Current SECOND: 36

Example 3: Calendar class getMaximum() method

  
  import java.util.Calendar;
  public class CalendarExample3 {
    public static void main(String[] args) {
      Calendar calendar = Calendar.getInstance();
      
      int max = calendar.getMaximum(Calendar.DAY_OF_WEEK);
      System.out.println("Maximum number of days in a week: " + max);
      
      max = calendar.getMaximum(Calendar.WEEK_OF_YEAR);
      System.out.println("Maximum number of weeks in a year: " + max);
    }
  }

Output

Maximum number of days in a week: 7
Maximum number of weeks in a year: 53

Example 4: Calendar class getMinimum() method

  
  import java.util.Calendar;
  public class CalendarExample4 {
    public static void main(String[] args) {
      Calendar calendar = Calendar.getInstance();
      
      int min = calendar.getMinimum(Calendar.DAY_OF_WEEK);
      System.out.println("Minimum number of days in week: " + min);
      
      min = calendar.getMinimum(Calendar.WEEK_OF_YEAR);
      System.out.println("Minimum number of weeks in year: " + min);
    }
  }

Output

Minimum number of days in week: 1
Minimum number of weeks in year: 1

Reference: https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Calendar

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Calendar Class in Java

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