[crac] RFR: X11 CRaC reinitializing on CheckpointRestore [v2]

Mon Sep 12 07:37:50 UTC 2022

> Allows CRaC to perform a CheckpointRestore operation for applications using GUI (Swing, AWT) and X11 connection.
> 
> Resources are registered only if the application uses the GUI. The order in which resources are reinitialized matters: Toolkit should be cleared before reference handling for a proper garbage collection, and GraphicsEnvironment after handling for a correct X11 disconnection. Some resources restore lazily.
> 
> The `beforeCheckpoint()` operation dispose necessary toolkit and connection resources and disconnects from X11. This allows CRaC to perform a Checkpoint since there is no external connection.
> The `afterRestore()` operations reconnect to X11 and then restore necessary connection and toolkit resources.
> 
> Thus, after the Restore operation, we have a clean X11 connection. It is ready to restore the original GUI state.

Kuznetsov Ilya Alexandrovich has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 74 additional commits since the last revision:

 - Minimize changes
 - Merge remote-tracking branch 'origin/x11-dev' into remote-x11-dev
 - Reduce public interfaces using AWTAccessor and package-private, made some code and docs improvements

   Signed-off-by: kznts9v-1lya <kuznetsov.ilya.alexandrovich at gmail.com>
 - Change AWT part of reinitialization using AWTAccessor

   Signed-off-by: kznts9v-1lya <kuznetsov.ilya.alexandrovich at gmail.com>
 - Change Disposer reinitialization using AWTAccessor

   Signed-off-by: kznts9v-1lya <kuznetsov.ilya.alexandrovich at gmail.com>
 - Disposer reinitialization using SharedSecrets

   Signed-off-by: kznts9v-1lya <kuznetsov.ilya.alexandrovich at gmail.com>
 - Fix in tests

   Signed-off-by: kznts9v-1lya <kuznetsov.ilya.alexandrovich at gmail.com>
 - Made some fixes

   Signed-off-by: kznts9v-1lya <kuznetsov.ilya.alexandrovich at gmail.com>
 - Merge remote-tracking branch 'upstream2/refqueue-2' into x11-dev

   # Conflicts:
   #	src/java.base/share/classes/jdk/internal/crac/JDKResource.java
 - Make jdk.crac.Misc final
 - ... and 64 more: https://git.openjdk.org/crac/compare/aa7fa48d...2f8751d1

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

Changes:
  - all: https://git.openjdk.org/crac/pull/19/files
  - new: https://git.openjdk.org/crac/pull/19/files/494e482d..2f8751d1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=19&range=01
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=19&range=00-01

  Stats: 1145 lines in 28 files changed: 588 ins; 412 del; 145 mod
  Patch: https://git.openjdk.org/crac/pull/19.diff
  Fetch: git fetch https://git.openjdk.org/crac pull/19/head:pull/19

PR: https://git.openjdk.org/crac/pull/19