abstract long fn(long currentValue, long newValue);

  /**
   * Handles cases of updates involving initialization, resizing, creating new Cells, and/or
   * contention. See above for explanation. This method suffers the usual non-modularity problems of
   * optimistic retry code, relying on rechecked sets of reads.
   *
   * @param x the value
   * @param hc the hash code holder
   * @param wasUncontended false if CAS failed before call

   *       into the other buffer (userspace). Note that if the file is very large, a naive
   *       implementation will effectively put the whole file in memory. On many systems with paging
   *       and virtual memory, this is not a problem - because it is mapped read-only, the kernel
   *       can always page it to disk "for free". However, on systems where killing processes

  JAVA_HOME("java.home"),

  /** Java Virtual Machine specification version. */
  JAVA_VM_SPECIFICATION_VERSION("java.vm.specification.version"),

  /** Java Virtual Machine specification vendor. */
  JAVA_VM_SPECIFICATION_VENDOR("java.vm.specification.vendor"),

  /** Java Virtual Machine specification name. */
  JAVA_VM_SPECIFICATION_NAME("java.vm.specification.name"),

  /** Java Virtual Machine implementation version. */

   * interpreted as an unsigned 64-bit value. Specifically, the sign bit of {@code bits} is
   * interpreted as a normal bit, and all other bits are treated as usual.
   *
   * <p>If the argument is nonnegative, the returned result will be equal to {@code bits},
   * otherwise, the result will be equal to {@code 2^64 + bits}.
   *

  /**
   * Drains the queue as {@linkplain #drain(BlockingQueue, Collection, int, long, TimeUnit)}, but
   * with a different behavior in case it is interrupted while waiting. In that case, the operation
   * will continue as usual, and in the end the thread's interruption status will be set (no {@code
   * InterruptedException} is thrown).
   *
   * @param q the blocking queue to be drained
   * @param buffer where to add the transferred elements

 * autoboxing and varargs array creation may happen as well, even when the verification succeeds and
 * the message ends up unneeded. Performance-sensitive verification checks should continue to use
 * usual form:
 *
 * <pre>{@code
 * Bill bill = remoteService.getLastUnpaidBill();
 * if (bill.status() != Status.UNPAID) {
 *   throw new VerifyException("Unexpected bill status: " + bill.status());
 * }
 * }</pre>
 *

   * expect, but there are some subtleties. First, we do guarantee that, if the output future at
   * index n is done, the output future at index n-1 is also done. (But as usual with futures, some
   * listeners for future n may complete before some for future n-1.) However, it is possible, if
   * one input completes with result X and another later with result Y, for Y to come before X in

    } catch (NoSuchElementException expected) {
    }

    try {
      iter.next();
      fail("next() should throw NoSuchElementException as usual");
    } catch (NoSuchElementException expected) {
    }

    try {
      iter.peek();
      fail("peek() should still throw NoSuchElementException after next()");
    } catch (NoSuchElementException expected) {

   * #expectContents(Object[]) expectContents(E...)} and other convenience methods. The creation of
   * multiple containers in a single method is discouraged in most cases, but it is vital to the
   * iterator tests.
   *
   * @return the new container instance
   * @param newValue the new container instance
   */
  @CanIgnoreReturnValue
  protected C resetContainer(C newValue) {

  abstract long fn(long currentValue, long newValue);

  /**
   * Handles cases of updates involving initialization, resizing, creating new Cells, and/or
   * contention. See above for explanation. This method suffers the usual non-modularity problems of
   * optimistic retry code, relying on rechecked sets of reads.
   *
   * @param x the value
   * @param hc the hash code holder
   * @param wasUncontended false if CAS failed before call