During the code review of JDK-8232230, comments were made that improvements could be made to the precision of the declared types of fields in several Serializable classes of java.util.concurrent.
Comments
If we ever envision a time when Java had intersection types, we could declare the private Condition fields in various classes as
private final Condition & Serializable notEmpty;
Alternatively, we could declare them
private final ConditionObject notEmpty;
but that would offend some software engineering purists.