Where do enums live?

[Denise Advincula]

Please correct me if my understanding is wrong. Enums are not objects. Enums are actually just ENUMS.

(There's a java.lang.Enum in the API. I am doubtful if they're the same though)

They can be declared inside and outside classes.

When enums are declared inside a class, and upon instantiation of that class, (1) they live on the heap. Hence (2) they're treated as class variables, or instance variables of that class.

Are (1) and (2) correct?

What happens when the enums are declared outside the class. Upon usage (or upon indirect invocation of constructors if they have) where do they live?

[ June 21, 2008: Message edited by: Denise Saulon ]
[ June 21, 2008: Message edited by: Denise Saulon ]

[Jesper de Jong]

An enum is a special kind of class. The constants of the enum are instances of that special classlike object; they are on the heap, just like other objects.

[Antonio Tercero]

Enums are a kind of special class:
-They can declare a constructor
-They can declare methods
-You can override methods

Example:

enum Day {
// overrides method toString()
S("Sunday") {
public String toString() {
return "Sunday(First day of week)";
}
},
M("Monday"), // invokes constructor Day(String)
T; // invokes constructor Day()
 
private String day;
 
Day() {
this.day = "Tuesday";
}
 
// Constructor
Day(String day) {
this.day = day;
}
 
public String getDay() {
return this.day;
}
 
}
 
public class Test {
public static void main(String args[]) {
      Day sunday=Day.S;
      Day monday=Day.M;
      Day tuesday=Day.T;
      
      System.out.println(sunday); // prints "Sunday(First day of week)"
      System.out.println(sunday.getDay()); // prints "Sunday"
      System.out.println(monday); // prints "M"
      System.out.println(monday.getDay()); // prints "Monday"
      System.out.println(tuesday); // prints "T"
      System.out.println(tuesday.getDay()); // prints "Tuesday"
      
}
}