In the class description of JapaneseEra class, there is a description about the public singleton of the class. In there, "subsequent versions of this class" is ambiguous as to whether it refers to the later platform releases or update releases which are already released. The following diff can clarify the ambiguity:
Once an era is defined,
- * subsequent versions of this class will add a singleton instance
+ * future versions of the platform may add a singleton instance
* for it.