src/java.base/share/classes/java/util/concurrent/Exchanger.java

8234131: Miscellaneous changes imported from jsr166 CVS 2021-01
Reviewed-by: martin

*** 55,77 ****
   * buffer gets a freshly emptied one when it needs it, handing off the
   * filled one to the thread emptying the buffer.
   * <pre> {@code
   * class FillAndEmpty {
   *   Exchanger<DataBuffer> exchanger = new Exchanger<>();
!  *   DataBuffer initialEmptyBuffer = ... a made-up type
!  *   DataBuffer initialFullBuffer = ...
   *
   *   class FillingLoop implements Runnable {
   *     public void run() {
   *       DataBuffer currentBuffer = initialEmptyBuffer;
   *       try {
   *         while (currentBuffer != null) {
   *           addToBuffer(currentBuffer);
   *           if (currentBuffer.isFull())
   *             currentBuffer = exchanger.exchange(currentBuffer);
   *         }
!  *       } catch (InterruptedException ex) { ... handle ... }
   *     }
   *   }
   *
   *   class EmptyingLoop implements Runnable {
   *     public void run() {
--- 55,77 ----
   * buffer gets a freshly emptied one when it needs it, handing off the
   * filled one to the thread emptying the buffer.
   * <pre> {@code
   * class FillAndEmpty {
   *   Exchanger<DataBuffer> exchanger = new Exchanger<>();
!  *   DataBuffer initialEmptyBuffer = ...; // a made-up type
!  *   DataBuffer initialFullBuffer = ...;
   *
   *   class FillingLoop implements Runnable {
   *     public void run() {
   *       DataBuffer currentBuffer = initialEmptyBuffer;
   *       try {
   *         while (currentBuffer != null) {
   *           addToBuffer(currentBuffer);
   *           if (currentBuffer.isFull())
   *             currentBuffer = exchanger.exchange(currentBuffer);
   *         }
!  *       } catch (InterruptedException ex) { ... handle ...}
   *     }
   *   }
   *
   *   class EmptyingLoop implements Runnable {
   *     public void run() {