# Background Tasks { #background-tasks }

You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

                }
            }
            // For MSAL4J, if silent refresh fails, return true if token is still valid
            // Actual refresh will happen during next authentication request
            return true;
        }

        /**
         * Gets the Azure AD authentication result.
         * @return The authentication result.
         */

        // Then - nothing should happen (empty implementation)
        verifyNoInteractions(request);
    }

    @Test
    @DisplayName("Should setup response correctly")
    void testSetupResponse() {
        // Given
        Response resp = mock(Response.class);

        // When
        response.setupResponse(resp);

        // Then - nothing should happen (empty implementation)

     * are atomic, but do not provide happens-before ordering; however:
     *
     * <ul>
     *   <li>If this field's value == currentThread, we know that it's up to date, because write
     *       operations in a thread always happen-before subsequent read operations in the same
     *       thread

   * cached value, which will be recalculated when {@code get()} is called on the reserialized
   * instance. The actual memoization does not happen when the underlying delegate throws an
   * exception.
   *
   * <p>When the underlying delegate throws an exception then this memoizing supplier will keep
   * delegating calls until it returns valid data.
   *

    try {
      in.copyTo(out);
      fail();
    } catch (IOException expected) {
      return expected.getSuppressed().length;
    }
    throw new AssertionError(); // can't happen
  }

  private static CharSource newNormalCharSource() {
    return CharSource.wrap("ABC");
  }

  private static CharSink newNormalCharSink() {
    return new CharSink() {
      @Override

          @Override
          public void run() {
            do {
              // We can't have a GOLDEN_NOT_PRESENT_KEY because false positives are
              // possible! It's false negatives that can't happen.
              assertThat(bloomFilter.mightContain(GOLDEN_PRESENT_KEY)).isTrue();

              int key = getNonGoldenRandomKey();
              // We can't check that the key is mightContain() == false before the

        SmbTreeConnectionTrace wrapper = new SmbTreeConnectionTrace(delegate);
        wrapper.acquire();
        wrapper.release();

        // Assert: delegate interactions occur when usage transitions happen
        verify(delegate, times(1)).acquire();
        verify(delegate, times(1)).release();
    }

    @Test
    @DisplayName("finalize() invokes checkRelease exactly once")

        when(cfg.getBufferCacheSize()).thenReturn(2);
        when(cfg.getMaximumBufferSize()).thenReturn(5);

        BufferCacheImpl impl = new BufferCacheImpl(cfg);

        // Verify interactions happen exactly once during construction
        verify(cfg, times(1)).getBufferCacheSize();
        verify(cfg, times(1)).getMaximumBufferSize();
        verifyNoMoreInteractions(cfg);

    id: description
    attributes:
      label: Description
      description: |
        What is the problem, question, or error?

        Write a short description telling me what you are doing, what you expect to happen, and what is currently happening.
      placeholder: |
        * Open the browser and call the endpoint `/`.
        * It returns a JSON with `{"Hello": "World"}`.
        * But I expected it to return `{"Hello": "Sara"}`.