finishedSessionIdList.add(sessionId);
        }
    }

    /**
     * Deletes all data associated with a specific crawler session.
     * Removes URL filters, URL queues, and access result data for the session.
     *
     * @param sessionId the session ID whose data should be deleted
     */
    private void deleteBySessionId(final String sessionId) {
        try {

    assertFalse(segment.clearValueForTesting(key, hash, valueRef));
    segment.setWeakValueReferenceForTesting(entry, valueRef);
    assertTrue(segment.clearValueForTesting(key, hash, valueRef));
  }

  // reference queues

  public void testDrainKeyReferenceQueueOnWrite() {
    for (MapMaker maker : allWeakKeyStrengthMakers()) {
      MapMakerInternalMap<Object, Object, ?, ?> map = makeMap(maker.concurrencyLevel(1));

    assertFalse(segment.clearValueForTesting(key, hash, valueRef));
    segment.setWeakValueReferenceForTesting(entry, valueRef);
    assertTrue(segment.clearValueForTesting(key, hash, valueRef));
  }

  // reference queues

  public void testDrainKeyReferenceQueueOnWrite() {
    for (MapMaker maker : allWeakKeyStrengthMakers()) {
      MapMakerInternalMap<Object, Object, ?, ?> map = makeMap(maker.concurrencyLevel(1));

      it.next();
      it.remove();
    }
    segment.evictEntries(entry);
    assertThat(map).hasSize(maxSize);
    assertThat(map).isEqualTo(originalMap);
  }

  // reference queues

  public void testDrainKeyReferenceQueueOnWrite() {
    for (CacheBuilder<Object, Object> builder : allKeyValueStrengthMakers()) {
      LocalCache<Object, Object> map = makeLocalCache(builder.concurrencyLevel(1));

      it.next();
      it.remove();
    }
    segment.evictEntries(entry);
    assertThat(map).hasSize(maxSize);
    assertThat(map).isEqualTo(originalMap);
  }

  // reference queues

  public void testDrainKeyReferenceQueueOnWrite() {
    for (CacheBuilder<Object, Object> builder : allKeyValueStrengthMakers()) {
      LocalCache<Object, Object> map = makeLocalCache(builder.concurrencyLevel(1));

        return true;
    }

    /**
     * Stores child URLs from the given set into the crawling queue for future processing.
     * This method filters out blank URLs and increments the depth for child URLs.
     *
     * @param urlQueue the parent URL queue item
     * @param childUrlSet the set of child URLs to be queued for crawling
     */

                }
            }
        }
        return OptionalEntity.empty();
    }

    /**
     * Processes the search log queue.
     *
     * @param queue The search log queue.
     */
    protected void processSearchLogQueue(final Queue<SearchLog> queue) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String value = fessConfig.getPurgeByBots();
        String[] botNames;

    /**
     * Maximum size of the thumbnail generation task queue.
     */
    protected int thumbnailTaskQueueSize = 10000;

    /**
     * Number of tasks to process in bulk operations.
     */
    protected int thumbnailTaskBulkSize = 100;

    /**
     * Timeout in milliseconds for thumbnail task queue operations.
     */
    protected long thumbnailTaskQueueTimeout = 10 * 1000L;

  private void weaklyReferenceQueue() {
    frq = new FinalizableReferenceQueue();
    queueReference = new WeakReference<>(frq.queue);

    /*
     * Queue and clear a reference for good measure. We test later on that
     * the finalizer thread stopped, but we should test that it actually
     * started first.
     */
    reference =

### Crawler (`Crawler.java`)

Main orchestrator for crawling operations.

**Key Methods**:
```java
String execute()                // Start crawling, return session ID
void addUrl(String url)         // Add URL to queue
void cleanup(String sessionId)  // Clean up session
void stop()                     // Stop gracefully
```

**Key Fields**: `crawlerContext`, `urlFilter`, `intervalController`, `clientFactory`, `ruleManager`