ADDITIONAL JAVA TOPICS - Java Programming: From Problem Analysis to Program Design - page 985

4. Once an enum type is created, you can declare reference variables of that type, but
you cannot

instantiate objects using the operator new . In fact, an attempt to

instantiate an object using the operator new will result in a compilation error.
(Because enum objects cannot be instantiated using the operator new , the constructor, if
any, of an enumeration cannot be public . In fact, the constructors of an enum type are
implicitly private .)
The enum type Grades was defined earlier in this section. Let us redefine this enum type
by adding constructors, data members, and methods. Consider the following definition:

public enum Grades
{

A ("Range 90% to 100%"),
B ("Range 80% to 89.99%"),
C ("Range 70% to 79.99%"),
D ("Range 60% to 69.99%"),
F ("Range 0% to 59.99%");

private final String range;

private Grades()
{

range = "";

}

private Grades(String str)
{

range = str;

}

public String getRange()
{

return range;

}

}

This enum type Grades contains the enum constants A , B , C , D , and F . It has a private
named constant range of the type String , two constructors, and the method getRange .
Note that each Grades object has the data member range . Let us consider the statement:

A ("Range 90% to 100%")
This statement creates the Grades object, using the constructor with parameters, with the
string "Range 90% to 100%" , and assigns that object to the reference variable A . The
method getRange is used to return the string contained in the object.
It is not necessary to specify the modifier private in the heading of the constructor.
Each constructor is implicitly private . Therefore, the two constructors of the enum type
Grades can be written as: