JAVA EE: Java Tutorial: Enum in java[How to define a constructor in enum]

Friday, 5 May 2017

Java Tutorial: Enum in java[How to define a constructor in enum]

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Java Tutorial: Enum in java[How to define a constructor in enum]

EnumDemo.java

public class EnumDemo
{

    private enum Day
    {
        MONDAY(1), TUESDAY(2), WEDNESDAY(3), THURSDAY(4), FRIDAY(5), SATURDAY(6),
                                                                    SUNDAY(7);

        private int whichDay;

        /*
         * Constructor of enum type is private. If you don't
         * declare private compiler internally creates
         * private constructor.
         */
        private Day(int whichDay)
        {
            this.whichDay = whichDay;
        }

    }

    public static void main(String[] args)
    {
        /*
         * The java compiler internally adds the values()
         * method when it creates an enum. The values()
         * method returns an array containing all the values
         * of the enum.
         */
        Day[] daysArray = Day.values();
        for (Day day : daysArray)
        {
            System.out.println(day + " is which day? " + day.whichDay);
        }

    }
}

Output

MONDAY is which day? 1
TUESDAY is which day? 2
WEDNESDAY is which day? 3
THURSDAY is which day? 4
FRIDAY is which day? 5
SATURDAY is which day? 6
SUNDAY is which day? 7