Studyon Minte9.com
Fundamentals (Docs)

Study

Enum Types



An enum type is a type whose fields consist of a fixed set of constants. 
Common examples include compass directions (values of NORTH, SOUTH, EAST, and WEST) and the days of the
 week.
Because they are constants, the names of an enum type's fields are in uppercase letters.
	public enum Day {
	    SUNDAY, MONDAY, TUESDAY, WEDNESDAY, 
	    THURSDAY, FRIDAY, SATURDAY 
	}

Java programming language enum types are much more powerful than their counterparts in other languages. 
The enum declaration defines a class (called an enum type). The enum class body can include methods and other 
fields. 
The compiler automatically adds some special methods when it creates an enum.
	for (Planet p : Planet.values()) {
	    System.out.printf("Your weight on %s is %f%n",
				  p, p.surfaceWeight(mass));
	}

All enums implicitly extend java.lang.Enum. 
Since Java does not support multiple inheritance, an enum cannot extend anything else.


http://docs.oracle.com/javase/tutorial/java/javaOO/enum.html