Enum declaration in a method

Question

An enum can be declared inside or outside a class, but can't be declared in a method.
Can anyone tell that what is the problem with it. for what reason this restriction exist?
Thanks in advance

Answer 1

Karanjit is right. Nested interfaces and enums both are implicitly static. And their Constants are always (also when defined in top level) implicitly static. As we can't have static types inside a method we can't define enum in a method.
I read in "Sun Certified Programmer for Java 5 Study Guide" written by Bert Bates and Kathy Sierra that if we have following enum:
enum CoffeeSize { BIG, HUGE, OVERWHELMING }then we can think of this enum as a kind of class, that looks something (but not exactly) like this:
class CoffeeSize {
     public static final CoffeeSize BIG = new CoffeeSize("BIG", 0);
     public static final CoffeeSize HUGE = new CoffeeSize("HUGE", 1);
     public static final CoffeeSize OVERWHELMING = new CoffeeSize(
               "OVERWHELMING", 2);
     public CoffeeSize(String enumName, int index) {
          // stuff here
     public static void main(String[] args) {
          System.out.println(CoffeeSize.BIG);
}Also see this code which is compilable:
class HaveEnum {
     enum Colours {
          BLACK, WHITE
     static class StaClass {
          public static final StaClass sc = new StaClass();
     class InstClass {
          public final InstClass ic = new InstClass(); // can't be declared static
public class General {
     public static void main(String[] args) {
          HaveEnum.StaClass hes = HaveEnum.StaClass.sc; // (1)
          HaveEnum.Colours col = HaveEnum.Colours.BLACK; // (2)
          HaveEnum he = new HaveEnum(); // (3)
          HaveEnum.InstClass hei = he.new InstClass().ic; // (4)
}We can have enum constant BLACK in General class (at (2)) in similar way as StaClass constant sc (at (1)). If enum Colours were instant type like InstClass inner class then for having BLACK constant in General we would have to first instantiate HaveEnum class (like at (3)) and then using its object reference we could get BLACK constant (something like this) (like for InstClass at (4)):
HaveEnum he = new HaveEnum();
HaveEnum.Colours col = he.new Colours().BLACK;Note that main() method will throw StackOverflowError at runtime because (4) tries to recursively create another InstClass object.