Java枚举，每个常量如何以及何时分配内存

Question

I have simple enum class as given below. i want to know how memory is allocated to each constant( is Member class object is created for each constant) and what is its scope.

public enum Member {
    HAPPY("HAPPY"),RAhul("RAhul"),ANSAL("ANSAL");
    private String argument;

    Member(String arguments)
    {
        System.out.println("Enum Constructor work");
        this.argument = arguments;

    }
    public String getValue() {
        return argument;
    }

}

Answer 1

The members HAPPY("HAPPY"),RAhul("RAhul"),ANSAL("ANSAL"); are created when the enum class is loaded (ie their scope is static). Enums are compiled to normal classes that extend java.lang.Enum and its instances are allocated in the heap like other class objects.

Each member invokes the constructor that's defined in the enum which takes the string parameter.

This is from the relevant section in the Java Language Specification :

An enum constant may be followed by arguments, which are passed to the constructor of the enum type when the constant is created during class initialization as described later in this section. The constructor to be invoked is chosen using the normal overloading rules (§15.12.2). If the arguments are omitted, an empty argument list is assumed.

Answer 2

For all practical purposes, java considers enum as a class which can only has fixed number of Objects (an object corresponding to each enum constant defined). So enum is pretty much acts like a class in loading, initializing etc.