RFR: 8333344: JMX attaching of Subject does not work when security manager not allowed [v16]

[Daniel Fuchs]

On Mon, 17 Jun 2024 12:54:44 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

>> JMX uses APIs related to the Security Mananger which are deprecated.  Use of AccessControlContext will be removed when Security Manager is removed.
>> 
>> Until then, updates are needed to not require setting  -Djava.security.manager=allow to use JMX authentication.
>
> Kevin Walls has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - style update
>  - whitespace

The new version looks much better to me. I wonder if we can abstract away some of the repeated logic though.

src/java.management.rmi/share/classes/javax/management/remote/rmi/RMIConnectionImpl.java line 1314:

> 1312:                     return AccessController.doPrivileged(action, acc);
> 1313:                 }
> 1314:             }

This piece of code is repeated at several places in similar but different forms - sometime we check for `SharedSecrets.getJavaLangAccess().allowSecurityManager()`, sometime for `! SharedSecrets.getJavaLangAccess().allowSecurityManager()`, sometime we check for `acc == null`, sometime for `acc != null` etc.. 
I wonder if we could abstract that to some utility method somewhere. Would that make sense? Maybe that's not possible due to using sometime `PrivelegedAction` and sometimes `PrivilegedExceptionAction` - but maybe we could use `PrivilegedExceptionAction` everywhere at the cost of handling `PrivilegedActionException`? 
If that doesn't prove useful (if handling `PrivilegedExceptionAction` adds again an equivalent amount of clutter) then maybe we could at least make sure we do the same checks in the same way (typically `acc == null` vs `acc != null`)?

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PR Review: https://git.openjdk.org/jdk/pull/19624#pullrequestreview-2118725434
PR Review Comment: https://git.openjdk.org/jdk/pull/19624#discussion_r1642864523