RFR: 8265372: Simplify PKCS9Attribute [v4]

[Ben Perez]

On Thu, 11 Jan 2024 23:42:31 GMT, Ben Perez <duke at openjdk.org> wrote:

>> Refactored PKCS9Attribute to use a hash map instead of multiple arrays. The key for the hash map is an `ObjectIdentifier` and the values are a record `AttributeInfo` that stores the information previously contained in the arrays `PKCS9_VALUE_TAGS`, `VALUE_CLASSES`, and `SINGLE_VALUED`. 
>> 
>> It seems as though we should be able to get rid of constants such as `EMAIL_ADDRESS_OID` since they aren't heavily used with the hash map approach, but since the values are public it might cause compatibility issues.
>> 
>> Another question is how to handle `RSA DSI`, `S/MIME`, `Extended-certificate`, and `Issuer Serial Number` OIDs. The prior version threw an error but in this refactor they are treated as an "unknown OID" and only throw a debug warning. This was addressed in https://bugs.openjdk.org/browse/JDK-8011867 but prior to this refactor the aforementioned OIDs were treated differently than unknown OIDs.
>
> Ben Perez has updated the pull request incrementally with one additional commit since the last revision:
> 
>   removed calls to Class.forName

src/java.base/share/classes/sun/security/pkcs/PKCS9Attribute.java line 467:

> 465:             DerInputStream dis = new DerInputStream(elems[0].toByteArray());
> 466:             value = dis.getTime();
> 467:             break;

The current changes both: 
1. Removes the `elemTag` variable since it is never used and calling `getTag()` does not change `elems`.
2. Simply sets `value = elems[0].getTime()` so as to avoid the conversion to a `DerInputStream` and back.

Neither of these changes caused problems when testing but I wanted to double check before the PR gets merged.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17132#discussion_r1449557089