Java中这是什么类型的变量声明

Question

class FreshJuice {
   enum FreshJuiceSize{ SMALL, MEDIUM, LARGE }
   FreshJuiceSize size;
}

What type of variable is size ?

Is FreshJuiceSize size; a shorhand way of declaring size as a instance variable ?

Answer 1

In your example, size is a member variable with type FreshJuiceSize (an enum constrained to the 3 values you defined).

Perhaps what makes it look unusual is the absence of an access modifier: public , protected or private . For a member with no declared access modifier, it is "package-private", meaning that other classes within the same package may access it, but classes outside the package may not. The Java documentation on Controlling Access to Members of a Class describes this.

Answer 2

Yes. The variable type of size is enum FreshJuiceSize .

Answer 3

Is FreshJuiceSize size; a shorhand way of declaring size as a instance variable ?

You are just creating a reference of type FreshJuiceSize which is an enum with a set of predefined constants . There is no "short hand" or "long hand".

Answer 4

Size是FreshJuiceSize类型的变量FreshJuiceSize是一个枚举，因此大小仅采用{SMALL，MEDIUM，LARGE}集之一

Answer 5

FeshJuice is a class - most likely private - not main - judging by the lack of public class classname declaration - FreshJuiceSize is the enum name (similar to the name of an array), and FreshJuiceSize size; declares the variable size to be a member (I forget the term) of FreshJuiceSize