高级自定义 > 服务和基础结构自定义 > Evolvable 类 > Evolvable 类生成的外部化代码示例 > 生成的常量的示例
  
生成的常量的示例
static final long serialVersionUID = 1;
public static final long EXTERNALIZATION_VERSION_UID = 6676079877272797361L;
protected static final long OLD_FORMAT_VERSION_UID = -6779867937001963664L;
// OLD_FORMAT_VERSION_UID is only valid for R4 instances of the class