RFR: 8360463: Ambiguity in Cipher.getInstance() specification between NoSuchAlgorithmException and NoSuchPaddingException [v2]

[Weijun Wang]

On Wed, 13 Aug 2025 00:04:18 GMT, Valerie Peng <valeriep at openjdk.org> wrote:

>> This PR is for clarifying the `NoSuchAlgorithmException` and `NoSuchPaddingException` for the `Cipher.getInstance(String transformation, Provider provider)` and `Cipher.getInstance(String transformation, String provider)` methods.
>> 
>> As stated in `javax.crypto.CipherSpi` class, provider has the flexibility to register their implementations through various sub-transformations. As a result, depending on how the providers register the implementation, it may lead to `NoSuchAlgorithmException` or `NoSuchPaddingException`. For example, the provider A registers to support "AES/CBC/PKCS5Padding" vs provider B registers to support "AES" (but would only accept "CBC" and "PKCS5Padding" as the valid input for setting mode and padding). Calling `Cipher.getInstance(...)` with "AES/CBC/NoPadding" against provider A and B would lead to `NoSuchAlgorithmException` and `NoSuchPaddingException`. This javadoc update hope to make it clear.
>> 
>> Thanks in advance for the review~
>> Valerie
>
> Valerie Peng has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address review comments from Haimay.

Is it worth demonstrating the different behaviors with a test?

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PR Comment: https://git.openjdk.org/jdk/pull/26489#issuecomment-3181646988