RFR: 8256643: Terminally deprecate ThreadGroup stop, destroy, isDestroyed,… [v2]

[Alan Bateman]

> This change terminally deprecates the following methods defined by java.lang.ThreadGroup 
> 
> - stop 
> - destroy 
> - isDestroyed 
> - setDaemon 
> - isDaemon 
> 
> The stop method has been deprecated since=1.2 because it is inherently unsafe. It is time to terminally deprecate this method so it can be removed in a future release. Thread.stop will be examined in a separate issue. 
> 
> The destroy, isDestroyed, setDaemon, isDaemon methods support the mechanism to explicitly or automatically destroy a thread group. As detailed in JDK-8252885, the mechanism to destroy thread groups is flawed and racy. Furthermore, this mechanism inhibits efforts to drop the reference from a thread group to its threads (so that thread creation, starting and termination do not need to coordinate with their thread group). These methods should be terminally deprecated so they can be degraded in a future release and eventually removed.
> 
> CSR with more information:  https://bugs.openjdk.java.net/browse/JDK-8256644

Alan Bateman 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 four additional commits since the last revision:

 - Fixed typo in @deprecated text
 - Merge
 - Update jshell class
 - 8256643: Terminally deprecate ThreadGroup stop, destroy, isDestroyed, setDaemon and isDaemon

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1318/files
  - new: https://git.openjdk.java.net/jdk/pull/1318/files/c661861a..ca656ba1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1318&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1318&range=00-01

  Stats: 99634 lines in 382 files changed: 45266 ins; 43186 del; 11182 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1318.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1318/head:pull/1318

PR: https://git.openjdk.java.net/jdk/pull/1318