RFR [15] 6394757: rev2: AbstractSet.removeAll semantics are surprisingly dependent on relative sizes

[Stuart Marks]

>> The containsAll() and equals() methods both use the membership contract of the 
>> receiver, not the argument. Unfortunately, the equals() specification says,
>>
>>    Returns true if the specified object is also a set, the two sets have the
>>    same size, and every member of the specified set is contained in this set
>>    (or equivalently, every member of this set is contained in the specified
>>    set).
>>
>> As should be clear from this discussion, the "equivalently" clause is 
>> incorrect -- another spec bug.
> 
> Changing Set.equals() in this way would make Set inconsistent with Object.
> Do you really think that is a good idea?

     [example of asymmetry of equals]

Your example illustrates that the "equivalently" clause is incorrect. I prefer 
specifications to have fewer incorrect statements.

s'marks