RFR: 8267108: Alternate Subject.getSubject and doAs APIs that do not depend on Security Manager APIs

[Weijun Wang]

On Thu, 5 Aug 2021 20:10:44 GMT, Weijun Wang <weijun at openjdk.org> wrote:

> New `Subject` APIs `current()` and `callAs()` are created to be replacements of `getSubject()` and `doAs()` since the latter two methods are now deprecated for removal.
> 
> In this implementation, by default, `current()` returns the same value as `getSubject(AccessController.getCurrent())` and `callAs()` is implemented based on `doAs()`. This behavior is subject to change in the future once `SecurityManager` is removed.
> 
> User can experiment a possible future mechanism by setting the system property `jdk.security.auth.subject.useTL` to `true`, where the `callAs()` method stores the subject into a `ThreadLocal` object and the `current()` method returns it (Note: this mechanism does not work with principal-based permissions).
> 
> Inside JDK, we’ve switched from `getSubject()` to `current()` in JGSS and user can start switching to `callAs()` in their applications. Users can also switch to `current()` but please note that if you used to call `getSubject(acc)` in a `doPrivileged` call you might need to try calling `current()` in a `doPrivilegedWithCombiner` call to see if the `AccessControlContext` inside the call inherits the subject from the outer one.

test/jdk/javax/security/auth/Subject/FromACC.java line 9:

> 7:  * published by the Free Software Foundation.  Oracle designates this
> 8:  * particular file as subject to the "Classpath" exception as provided
> 9:  * by Oracle in the LICENSE file that accompanied this code.

Oops, no Classpath exception for this test.

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PR: https://git.openjdk.java.net/jdk/pull/5024