RFR: 8355379: Annotate lazy fields in java.security @Stable

[Per Minborg]

On Fri, 23 May 2025 04:54:26 GMT, Koushik Muthukrishnan Thirupattur <duke at openjdk.org> wrote:

> Several classes in the `java.security` package lazily compute their hash value and store it in a field. These fields can typically be annotated with the `@Stable` annotation. Many of the current implementations are using -1 as a flag for not computed, this needs to be refactored away.
> 
> Here are some examples of such classes: PKCS12Attribute, Timestamp, Certificate, and URICertStoreParameters.

I think we should add tests that seralizes/deserializes objects several times to make sure the hash code works as expected here.

src/java.base/share/classes/java/security/CodeSigner.java line 172:

> 170:             throw new InvalidObjectException("signerCertPath is null");
> 171:         }
> 172:         myhash = 0;

I do not think we can use `@Stable` for this class, as `readObject()` can be called multiple times on an object.

src/java.base/share/classes/java/security/Timestamp.java line 179:

> 177:             throw new InvalidObjectException("Invalid null field(s)");
> 178:         }
> 179:         myhash = 0;

Same here.

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PR Comment: https://git.openjdk.org/jdk/pull/25405#issuecomment-2939685005
PR Review Comment: https://git.openjdk.org/jdk/pull/25405#discussion_r2126373067
PR Review Comment: https://git.openjdk.org/jdk/pull/25405#discussion_r2126374887