Java中enum枚举的使用?报错

教材里面有段关于枚举的代码，但一直报错，麻烦高手看一下

import java.util. *;
    public class EnumTest {

        public static void main(String[] args) {
            Scanner in=new Scanner(System.in);
            System.out.print("请输入服装型号:(SMALL,MEDIUM,LARGE,EXTRA_LARGE,EXTRA_EXTRA_LARGE)");
            String input=in.next().toUpperCase();
            Size size=Enum.valueOf(Size.class,input);
            System.out.println("Size="+size);
            System.out.println("abbreviation="+size.getAbbreviation());
            if(size==Size.EXTRA_LARGE^size==Size.EXTRA_EXTRA_LARGE)
                System.out.println("很好，你注意到了下划线");

        }
        public static String abbreviation;
        enum Size{SMALL,MEDIUM,EXTRA_LARGE,EXTRA_EXTRA_LARGE}
        private void Size(String abbreviation){this.abbreviation=abbreviation;}
        public String getAbbreviation(){return abbreviation;}
    }