# 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:

                throw new RuntimeException("Operation timed out after 30 seconds");
            }
        };
        ComponentUtil.register(searchEngineClient, "searchEngineClient");

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

        // Assert error message is in the result
        assertTrue(result.contains("Operation timed out after 30 seconds"));
    }

    @Test

    assertThrows(NullPointerException.class, () -> getMap().putIfAbsent(null, v3()));
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported putIfAbsent(null, value)");
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPutIfAbsent_nullValueUnsupportedAndKeyAbsent() {

 */
@DoNotMock("Implement with a lambda")
@GwtCompatible
@NullMarked
public interface TearDownAccepter {
  /**
   * Registers a TearDown implementor which will be run after the test proper.
   *
   * <p>In JUnit4 language, that means as an {@code @After}.
   *
   * <p>In JUnit3 language, that means during the {@link junit.framework.TestCase#tearDown()} step.
   */
  void addTearDown(TearDown tearDown);

 */
@DoNotMock("Implement with a lambda")
@GwtCompatible
@NullMarked
public interface TearDownAccepter {
  /**
   * Registers a TearDown implementor which will be run after the test proper.
   *
   * <p>In JUnit4 language, that means as an {@code @After}.
   *
   * <p>In JUnit3 language, that means during the {@link junit.framework.TestCase#tearDown()} step.
   */
  void addTearDown(TearDown tearDown);

    /**
     * Initializes the processor after dependency injection.
     * Sets up the ingest factory if available in the component system.
     */
    @PostConstruct
    public void init() {
        if (ComponentUtil.hasIngestFactory()) {
            ingestFactory = ComponentUtil.getIngestFactory();
        }
    }

    /**
     * Creates an access result after processing the response data through ingesters.
     *

/**
 * Implemented by references that have code to run after garbage collection of their referents.
 *
 * @see FinalizableReferenceQueue
 * @author Bob Lee
 * @since 2.0
 */
@DoNotMock("Use an instance of one of the Finalizable*Reference classes")
@J2ktIncompatible
@GwtIncompatible
public interface FinalizableReference {
  /**
   * Invoked on a background thread after the referent has been garbage collected unless security

    assertThrows(NullPointerException.class, () -> getMap().putIfAbsent(null, v3()));
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported putIfAbsent(null, value)");
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  public void testPutIfAbsent_nullValueUnsupportedAndKeyAbsent() {

     * @param retryAfterSeconds the Retry-After header value
     * @throws IOException if an I/O error occurs
     */
    protected void sendRateLimitResponse(final HttpServletResponse response, final int retryAfterSeconds) throws IOException {
        response.setStatus(429); // Too Many Requests
        response.setContentType("application/json;charset=UTF-8");
        response.setHeader("Retry-After", String.valueOf(retryAfterSeconds));

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final int[] rowCounts;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final int[] columnCounts;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final @Nullable V[][] values;