// The recover built-in function allows a program to manage behavior of a
// panicking goroutine. Executing a call to recover inside a deferred
// function (but not any function called by it) stops the panicking sequence
// by restoring normal execution and retrieves the error value passed to the
// call of panic. If recover is called outside the deferred function it will
// not stop a panicking sequence. In this case, or when the goroutine is not

    boolean[] called = new boolean[1];
    f.addCallback(
        new FutureCallback<String>() {
          @Override
          public void onSuccess(String result) {
            called[0] = true;
          }

          @Override
          public void onFailure(Throwable t) {}
        },
        directExecutor());
    assertThat(called[0]).isTrue();
  }

    // JVM shutdown will not be prevented from exiting after this service has stopped or failed.
    // Technically this listener is added after start() was called so it is a little gross, but it
    // is called within doStart() so we know that the service cannot terminate or fail concurrently

Normally you use:

* `POST`: to create data.
* `GET`: to read data.
* `PUT`: to update data.
* `DELETE`: to delete data.

So, in OpenAPI, each of the HTTP methods is called an "operation".

We are going to call them "**operations**" too.

#### Define a *path operation decorator* { #define-a-path-operation-decorator }

{* ../../docs_src/first_steps/tutorial001.py hl[6] *}

                throw new RuntimeException("Delete operation failed");
            }
        };
        ComponentUtil.register(searchEngineClient, "searchEngineClient");

        // Execute the job
        String result = purgeDocJob.execute();

        // Assert error message is in the result
        assertTrue(result.contains("Delete operation failed"));
        assertTrue(result.endsWith("\n"));
    }

   * form does not contain the cached value, which will be recalculated when {@code get()} is called
   * on the deserialized instance.
   *
   * <p>When the underlying delegate throws an exception then this memoizing supplier will keep
   * delegating calls until it returns valid data.
   *
   * <p>If {@code delegate} is an instance created by an earlier call to {@code memoize}, it is
   * returned directly.
   */

          private boolean called = false;

          @Override
          public void onSuccess(String result) {
            fail("Was not expecting onSuccess() to be called.");
          }

          @Override
          public void onFailure(Throwable t) {
            synchronized (monitor) {
              assertFalse(called);
              assertThat(t).isInstanceOf(CancellationException.class);

     * caught above) can linger and affect listeners.
     */
  }

  /**
   * Called before runInterruptibly - if true, runInterruptibly and afterRanInterruptibly will not
   * be called.
   */
  abstract boolean isDone();

  /**
   * Do interruptible work here - do not complete Futures here, as their listeners could be
   * interrupted.

     *
     * @param level the logging level to set
     */
    public static void setLevel(final int level) {
        LogStream.level = level;
    }

    /**
     * This must be called before <code>getInstance</code> is called or
     * it will have no effect.
     *
     * @param stream the PrintStream to use for logging
     */
    public static void setInstance(final PrintStream stream) {

     */
    public interface RequestListener {

        /**
         * Called when a request starts.
         *
         * @param client the fault-tolerant client
         * @param request the request data
         */
        void onRequestStart(FaultTolerantClient client, RequestData request);

        /**
         * Called before each request attempt.
         *
         * @param client the fault-tolerant client