and Java’s <code>volatile</code> variables.
</p>

<h3 id="finalizer">Finalizers</h3>

<p>
The <a href="/pkg/runtime/"><code>runtime</code></a> package provides
a <code>SetFinalizer</code> function that adds a finalizer to be called when
a particular object is no longer reachable by the program.

        PreauthIntegrityContext context = sessionContexts.get(sessionId);
        return context != null ? context.getCurrentHash() : null;
    }

    /**
     * Finalizes and removes the preauth integrity context for a session.
     *
     * @param sessionId the session identifier
     */
    public void finalizeSession(String sessionId) {

                    throw new DictionaryException("Failed to write: " + item, e);
                }
            }
            return null;
        }

        /**
         * Closes the updater and finalizes the file update operation.
         * If changes were committed, the temporary file replaces the original.
         * Otherwise, the temporary file is deleted.
         */
        @Override
        public void close() {

    throw formatRuntimeException(
        "Latch failed to count down within %d second timeout", timeoutSeconds);
  }

  /**
   * Creates a garbage object that counts down the latch in its finalizer. Sequestered into a
   * separate method to make it somewhat more likely to be unreachable.
   */
  private static void createUnreachableLatchFinalizer(CountDownLatch latch) {
    Object unused =
        new Object() {

    throw formatRuntimeException(
        "Latch failed to count down within %d second timeout", timeoutSeconds);
  }

  /**
   * Creates a garbage object that counts down the latch in its finalizer. Sequestered into a
   * separate method to make it somewhat more likely to be unreachable.
   */
  private static void createUnreachableLatchFinalizer(CountDownLatch latch) {
    Object unused =
        new Object() {