RFR: JDK-8314272: Improve java.util.prefs.BackingStoreException: Couldn't get file lock.

[Matthias Baesken]

We run into some BackingStoreException: Couldn't get file lock. e.g. here :

[JShell] Exception in thread "main" java.lang.IllegalStateException: java.util.prefs.BackingStoreException: Couldn't get file lock.
[JShell] at jdk.jshell/jdk.internal.jshell.tool.JShellToolBuilder$PreferencesStorage.flush(JShellToolBuilder.java:313)
[JShell] at jdk.jshell/jdk.internal.jshell.tool.JShellTool$ReplayableHistory.storeHistory(JShellTool.java:692)
[JShell] at jdk.jshell/jdk.internal.jshell.tool.JShellTool.start(JShellTool.java:1008)
[JShell] at jdk.jshell/jdk.internal.jshell.tool.JShellToolBuilder.start(JShellToolBuilder.java:261)
[JShell] at jdk.jshell/jdk.internal.jshell.tool.JShellToolProvider.main(JShellToolProvider.java:120)
[JShell] Caused by: java.util.prefs.BackingStoreException: Couldn't get file lock.
[JShell] at java.prefs/java.util.prefs.FileSystemPreferences.sync(FileSystemPreferences.java:769)
[JShell] at java.prefs/java.util.prefs.FileSystemPreferences.flush(FileSystemPreferences.java:864)
[JShell] at jdk.jshell/jdk.internal.jshell.tool.JShellToolBuilder$PreferencesStorage.flush(JShellToolBuilder.java:311)
[JShell] ... 4 more

The BackingStoreException should be enhanced e.g. by adding the errno/errorCode that is already available in the coding

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

Commit messages:
 - JDK-8314272

Changes: https://git.openjdk.org/jdk/pull/15308/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15308&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314272
  Stats: 15 lines in 1 file changed: 5 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/15308.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15308/head:pull/15308

PR: https://git.openjdk.org/jdk/pull/15308