[EXPERIMENT] test with java 23

[pjfanning]

temporary test run but may be refactored later to run nightly

[pjfanning]

running into Java deprecations for methods on 'Unsafe' class

[info] compiling 208 Scala sources and 28 Java sources to /home/runner/work/pekko/pekko/actor/target/scala-2.13/classes ...
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/LightArrayRevolverScheduler.scala:373:63: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]         case x                                  => if (unsafe.compareAndSwapObject(this, taskOffset, x, replaceWith)) x else extractTask(replaceWith)
[error]                                                               ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/RepointableActorRef.scala:69:42: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]   def underlying: Cell = Unsafe.instance.getObjectVolatile(this, cellOffset).asInstanceOf[Cell]
[error]                                          ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/RepointableActorRef.scala:70:32: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]   def lookup = Unsafe.instance.getObjectVolatile(this, lookupOffset).asInstanceOf[Cell]
[error]                                ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/RepointableActorRef.scala:74:25: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     if (Unsafe.instance.compareAndSwapObject(this, cellOffset, old, next)) old else swapCell(next)
[error]                         ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/RepointableActorRef.scala:79:25: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     if (Unsafe.instance.compareAndSwapObject(this, lookupOffset, old, next)) old else swapLookup(next)
[error]                         ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:41:21: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.getObjectVolatile(this, AbstractActorCell.childrenOffset).asInstanceOf[ChildrenContainer]
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:68:21: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.getObjectVolatile(this, AbstractActorCell.functionRefsOffset).asInstanceOf[Map[String, FunctionRef]]
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:87:28: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]       if (!Unsafe.instance.compareAndSwapObject(this, AbstractActorCell.functionRefsOffset, old, added)) rec()
[error]                            ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:102:30: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]         if (!Unsafe.instance.compareAndSwapObject(this, AbstractActorCell.functionRefsOffset, old, removed)) rec()
[error]                              ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:114:8: method getAndSetObject in class Unsafe is deprecated (since 23)
[error]       .getAndSetObject(this, AbstractActorCell.functionRefsOffset, Map.empty)
[error]        ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:121:31: method getAndAddLong in class Unsafe is deprecated (since 23)
[error]     val num = Unsafe.instance.getAndAddLong(this, AbstractActorCell.nextNameOffset, 1)
[error]                               ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:125:31: method getAndAddLong in class Unsafe is deprecated (since 23)
[error]     val num = Unsafe.instance.getAndAddLong(this, AbstractActorCell.nextNameOffset, 1)
[error]                               ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:154:21: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.compareAndSwapObject(this, AbstractActorCell.childrenOffset, oldChildren, newChildren)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Children.scala:187:21: method putObjectVolatile in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.putObjectVolatile(this, AbstractActorCell.childrenOffset, TerminatedChildrenContainer)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Dispatch.scala:56:21: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.getObjectVolatile(this, AbstractActorCell.mailboxOffset).asInstanceOf[Mailbox]
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/actor/dungeon/Dispatch.scala:60:26: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     if (!Unsafe.instance.compareAndSwapObject(this, AbstractActorCell.mailboxOffset, oldMailbox, newMailbox))
[error]                          ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/AbstractDispatcher.scala:127:31: method getAndAddLong in class Unsafe is deprecated (since 23)
[error]     val old = Unsafe.instance.getAndAddLong(this, inhabitantsOffset, add)
[error]                               ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/AbstractDispatcher.scala:139:49: method getLongVolatile in class Unsafe is deprecated (since 23)
[error]   final def inhabitants: Long = Unsafe.instance.getLongVolatile(this, inhabitantsOffset)
[error]                                                 ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/AbstractDispatcher.scala:141:61: method getIntVolatile in class Unsafe is deprecated (since 23)
[error]   private final def shutdownSchedule: Int = Unsafe.instance.getIntVolatile(this, shutdownScheduleOffset)
[error]                                                             ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/AbstractDispatcher.scala:143:21: method compareAndSwapInt in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.compareAndSwapInt(this, shutdownScheduleOffset, expect, update)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/Mailbox.scala:124:61: method getIntVolatile in class Unsafe is deprecated (since 23)
[error]   final def currentStatus: Mailbox.Status = Unsafe.instance.getIntVolatile(this, AbstractMailbox.mailboxStatusOffset)
[error]                                                             ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/Mailbox.scala:137:21: method compareAndSwapInt in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.compareAndSwapInt(this, AbstractMailbox.mailboxStatusOffset, oldStatus, newStatus)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/Mailbox.scala:140:21: method putIntVolatile in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.putIntVolatile(this, AbstractMailbox.mailboxStatusOffset, newStatus)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/Mailbox.scala:213:23: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]       Unsafe.instance.getObjectVolatile(this, AbstractMailbox.systemMessageOffset).asInstanceOf[SystemMessage])
[error]                       ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/dispatch/Mailbox.scala:220:21: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.compareAndSwapObject(this, AbstractMailbox.systemMessageOffset, _old.head, _new.head)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/AskSupport.scala:[553](https://github.com/apache/pekko/actions/runs/11352818502/job/31576426284#step:6:554):21: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.getObjectVolatile(this, watchedByOffset).asInstanceOf[Set[ActorRef]]
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/AskSupport.scala:[556](https://github.com/apache/pekko/actions/runs/11352818502/job/31576426284#step:6:557):21: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.compareAndSwapObject(this, watchedByOffset, oldWatchedBy, newWatchedBy)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/AskSupport.scala:576:53: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]   private[this] def state: AnyRef = Unsafe.instance.getObjectVolatile(this, stateOffset)
[error]                                                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/AskSupport.scala:579:21: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.compareAndSwapObject(this, stateOffset, oldState, newState)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/AskSupport.scala:581:72: method putObjectVolatile in class Unsafe is deprecated (since 23)
[error]   private[this] def setState(newState: AnyRef): Unit = Unsafe.instance.putObjectVolatile(this, stateOffset, newState)
[error]                                                                        ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/CircuitBreaker.scala:321:21: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.compareAndSwapObject(this, AbstractCircuitBreaker.stateOffset, oldState, newState)
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/CircuitBreaker.scala:329:21: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.getObjectVolatile(this, AbstractCircuitBreaker.stateOffset).asInstanceOf[State]
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/CircuitBreaker.scala:335:21: method compareAndSwapObject in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.compareAndSwapObject(
[error]                     ^
[error] /home/runner/work/pekko/pekko/actor/src/main/scala/org/apache/pekko/pattern/CircuitBreaker.scala:345:21: method getObjectVolatile in class Unsafe is deprecated (since 23)
[error]     Unsafe.instance.getObjectVolatile(this, AbstractCircuitBreaker.resetTimeoutOffset).asInstanceOf[FiniteDuration]
[error]                     ^
[error] 34 errors found