枚举是如何实现的？（枚举的线程安全性及序列化问题）

1 public enum t {
2     SPRING,SUMMER,AUTUMN,WINTER;
3 }

 1 public final class T extends Enum
 2 {
 3     private T(String s, int i)
 4     {
 5         super(s, i);
 6     }
 7     public static T[] values()
 8     {
 9         T at[];
10         int i;
11         T at1[];
12         System.arraycopy(at = ENUM$VALUES, 0, at1 = new T[i = at.length], 0, i);
13         return at1;
14     }
15     public static T valueOf(String s)
16     {
17         return (T)Enum.valueOf(demo/T, s);
18     }
19     public static final T SPRING;
20     public static final T SUMMER;
21     public static final T AUTUMN;
22     public static final T WINTER;
23     private static final T ENUM$VALUES[];
24     static
25     {
26         SPRING = new T("SPRING", 0);
27         SUMMER = new T("SUMMER", 1);
28         AUTUMN = new T("AUTUMN", 2);
29         WINTER = new T("WINTER", 3);
30         ENUM$VALUES = (new T[] {
31             SPRING, SUMMER, AUTUMN, WINTER
32         });
33     }
34 }

 1         public static final T SPRING;
 2         public static final T SUMMER;
 3         public static final T AUTUMN;
 4         public static final T WINTER;
 5         private static final T ENUM$VALUES[];
 6         static
 7         {
 8             SPRING = new T("SPRING", 0);
 9             SUMMER = new T("SUMMER", 1);
10             AUTUMN = new T("AUTUMN", 2);
11             WINTER = new T("WINTER", 3);
12             ENUM$VALUES = (new T[] {
13                 SPRING, SUMMER, AUTUMN, WINTER
14             });
15         }

1 public enum EasySingleton{
2     INSTANCE;
3 }