RFR: 8358015: Fix SequencedMap sequenced view method specifications

[Stuart Marks]

On Fri, 30 May 2025 02:33:27 GMT, Chen Liang <liach at openjdk.org> wrote:

>> For a full explanation, see the bug report [JDK-8358015](https://bugs.openjdk.org/browse/JDK-8358015).
>> 
>> This PR includes three related changes:
>> * New overrides in SequencedMap view collection implementations, which improve their behavior.
>> * Update to `@implSpec` clauses to reflect this behavior (which was previously ill-specified).
>> * Update to a test which relied on unspecified behavior.
>
> src/java.base/share/classes/java/util/AbstractMap.java line 881:
> 
>> 879:         UnsupportedOperationException uoe() { return new UnsupportedOperationException(); }
>> 880:         // convert null entry return values into NSEE
>> 881:         <T> T nsee(T entry) {
> 
> Suggestion:
> 
>         <T extends Map.Entry<?, ?>> T nsee(T entry) {
> 
> So we don't accidentally use this on map keys or values.

Reasonable.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25515#discussion_r2116830360