RFR: 8283092: JMX subclass permission check redundant with strong encapsulation

[Kevin Walls]

On Tue, 15 Mar 2022 20:22:16 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

> Removing permission checks which, in the presence of a Security Manager, would check for a RuntimePermission "className.subclass".  This was to prevent subclassing these classes, but is no longer necessary with strong encapsulation from modules.

Added test update.  Checks that with permissive module options we can extend sun.management.spi.PlatformMBeanProvider, and that without them we cannot.

Output of the new test is like this:

----------System.out:(11/1279)----------
---PlatformMBeanProviderConstructorCheck:
---PlatformMBeanProviderConstructorCheck: invoke MyProvider with expectedFail = false
---PlatformMBeanProviderConstructorCheck PASSED (1) (expectedFail = false)
---PlatformMBeanProviderConstructorCheck: re-invoke without --add-modules or --add-exports
Command line: [/tank/kwalls/repos/personal/jdk/open/test/../../build/linux-x86_64-server-release/images/jdk/bin/java -cp /tank/kwalls/repos/personal/jdk/open/test/JTwork/classes/sun/management/PlatformMBeanProviderConstructorCheck.d:/tank/kwalls/repos/personal/jdk/open/test/jdk/sun/management:/tank/kwalls/repos/personal/jdk/open/test/JTwork/classes/test/lib:/tank/kwalls/repos/personal/jdk/open/test/lib:/opt/jtreg6.1/lib/javatest.jar:/opt/jtreg6.1/lib/jtreg.jar PlatformMBeanProviderConstructorCheck --nomoduleargs ]
[2022-03-18T17:19:34.798024163Z] Gathering output for process 10627
[2022-03-18T17:19:34.902532753Z] Waiting for completion for process 10627
[2022-03-18T17:19:34.902807078Z] Waiting for completion finished for process 10627
Output and diagnostic info for process 10627 was saved into 'pid-10627-output.log'
[2022-03-18T17:19:34.908368606Z] Waiting for completion for process 10627
[2022-03-18T17:19:34.908503964Z] Waiting for completion finished for process 10627
----------System.err:(9/647)----------
 stdout: [---PlatformMBeanProviderConstructorCheck:
---PlatformMBeanProviderConstructorCheck: invoke MyProvider with expectedFail = true
---PlatformMBeanProviderConstructorCheck got exception: java.lang.IllegalAccessError: superclass access check failed: class PlatformMBeanProviderConstructorCheck$MyProvider (in unnamed module @0x4795bbf5) cannot access class sun.management.spi.PlatformMBeanProvider (in module java.management) because module java.management does not export sun.management.spi to unnamed module @0x4795bbf5
---PlatformMBeanProviderConstructorCheck PASSED (2) (expectedFail = true)
];
 stderr: []
 exitValue = 0

STATUS:Passed.

-------------

PR: https://git.openjdk.java.net/jdk/pull/7827