<AWT Dev> Accessing internal packages in JDK 9

[Simon Nash]

I have recently discovered that applications will no longer be able
to access internal packages (sun.* and com.sun.*) in JDK 9.  This is a
major problem for my application as it requires access to some internal
packages in order to work correctly.

In most cases, my need to access these internal classes is to work around
"object leakage" in Swing that results in objects being created and held
by Swing with no means of freeing these objects by any application action.
In some cases, these "leaked" objects reference my application classloader
via their protection domain, and this means that my application classloader
cannot be garbage collected even if I remove all references to it from
within my application.  My application uses native DLLs that sometimes need
to be replaced by new versions and these DLLs cannot be unloaded and
reloaded unless the application classloader that loaded these DLLs has been
garbage collected.

The only workaround I have found for this problem is to use internal APIs
together with reflection to locate the fields that are holding these
internal "leaked" objects and set these fields to null.

It is hard to provide a definitive list of all the internal packages that
I need because the list tends to grow each time I use additional Swing
functionality in my application.  At present, the packages are:

sun.awt.AppContext
sun.awt.image.MultiResolutionToolkitImage$ObserverCache
sun.awt.X11.XBaseWindow
sun.lwawt.LWComponentPeer
sun.java2d.pipe.BufferedContext
sun.java2d.pipe.RenderQueue
sun.java2d.pipe.hw.BufferedContextProvider

In addition, my application is using some APIs from internal packages to
access functionality that isn't available via official APIs.  These aren't
Swing or AWT packages, so this mailing list probably isn't the right place
to go into details.  Any suggestions for the correct list(s) to raise this
issue would be appreciated.  The packages are:

com.sun.management.HotSpotDiagnosticMXBean
sun.misc.Signal
sun.misc.SignalHandler
sun.nio.ch.ChannelInputStream

Best regards,
Simon Nash