ENUMERATION ENUM IN JAVA in Hindi Lecture 119

//Enum in Java 1.Enum in java is a data type that contains fixed set of constants Example--- enum Season{WINTER,SUMMER,SPRING,FALL} 2.Enum is a special class that defines a set of constants 3.Variable of that type must be equal to one of constant values that have been pre-defined. Example –direction is already defined Enum Direction{NORTH,SOUTH,,EAST,WEST} 4.It can be used for Example--- 1.Days of Week {SUNDAY,MONDAY,….} 2.Months {JANUARY,FEBRUARY,MARCH,….} 3.Color {RED,GREEN,BLUE….} 4.Planets {MARS,JUPITER,EARTH…} 5.The java enum constants are public static and final implicitly like interface data members are public static final Example--- directions values are public static and final 6.It is available from JDK 1.5 7.Java enums contain only fixed set of constants 8.Java constants are written in UPPER-CASE letters like in java.math class it contain PI as capital letter. Example---enum Season{WINTER,SUMMER…} WINTER,SUMMER are written in UPPER-CASE 9.Example1- Public enum Direction {NORTH,SOUTH,EAST…} Similar in class Public class Direction {………} Example2--- Public enum Season{WITNTER,SUMMER,FALL..} Public static void main(String args[]) { Season obj=Season.WINTER; //EnumName.Constants } Note about Enum------ 1.enum improves type safety 2.enum can be easily used in switch as we give multiple choices in switch 3.enum can have data members,constructors and methods where as interface contain data members and abstract methods 4.enum may inherit or implement many interfaces but cannot inherit or extends any class because it internally extends enum class. 5.new constants can be added without breaking the existing code. Example- Public enum Season{WINTER,SUMER,AUTUM..} As in this example we have added new value AUTUM. //Use of Enum enum Direction{NORTH,SOUTH,EAST,WEST; } class example { public static void main(String args[]) { Direction obj=Direction.WEST; System.out.println("value="+obj); } }