file.delete();
            file.mkdirs();
            file.deleteOnExit();
            fileTransformer.setPath(file.getAbsolutePath());
            crawler.addUrl(url);
            crawler.crawlerContext.setMaxAccessCount(maxCount);
            crawler.crawlerContext.setNumOfThread(numOfThread);
            crawler.urlFilter.addInclude(url + ".*");

            file.delete();
            file.mkdirs();
            file.deleteOnExit();
            fileTransformer.setPath(file.getAbsolutePath());
            crawler.addUrl(url);
            crawler.crawlerContext.setMaxAccessCount(maxCount);
            crawler.crawlerContext.setNumOfThread(numOfThread);
            crawler.urlFilter.addInclude(url + ".*");

            file.delete();
            file.mkdirs();
            file.deleteOnExit();
            fileTransformer.setPath(file.getAbsolutePath());
            crawler.addUrl(url);
            crawler.getCrawlerContext().setMaxAccessCount(maxCount);
            crawler.getCrawlerContext().setNumOfThread(numOfThread);
            crawler.urlFilter.addInclude(url + ".*");

```java
// Create multiple crawler instances
Crawler crawler1 = container.getComponent("crawler");
crawler1.setSessionId("session1");
crawler1.addUrl("https://site1.com");

Crawler crawler2 = container.getComponent("crawler");  
crawler2.setSessionId("session2");
crawler2.addUrl("https://site2.com");

// Execute concurrently
crawler1.setBackground(true);
crawler2.setBackground(true);

     * @return true if the URL was successfully added to favorites, false if the user was not found
     */
    public boolean addUrl(final String userCode, final BiConsumer<UserInfo, FavoriteLog> favoriteLogLambda) {
        return userInfoBhv.selectByPK(userCode).map(userInfo -> {
            final FavoriteLog favoriteLog = new FavoriteLog();

 * the maximum depth of crawling, and URL filters.
 *
 * <p>Example usage:
 * <pre>
 *   Crawler crawler = new Crawler();
 *   crawler.addUrl("http://example.com/");
 *   crawler.execute();
 *   crawler.close();
 * </pre>
 */
public class Crawler implements Runnable, AutoCloseable {

            logger.debug("Populating class realm '" + extRealm.getId() + "'");

            for (Path file : extClassPath) {
                logger.debug("  included '" + file + "'");
                extRealm.addURL(file.toUri().toURL());
            }

            ArrayList<CoreExtensionEntry> reversed = new ArrayList<>(extensions);
            Collections.reverse(reversed);
            for (CoreExtensionEntry entry : reversed) {

---

## Key Components

### 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
```

            if (logger.isDebugEnabled()) {
                String id = getId(constituent);
                logger.debug("  Included: {}", id);
            }

            try {
                classRealm.addURL(file.toURI().toURL());
            } catch (MalformedURLException e) {
                // Not going to happen
                logger.error(e.getMessage(), e);
            }
        }
    }

                            throw new WebApiException(HttpServletResponse.SC_NOT_FOUND, "Not found: " + favoriteUrl);
                        }

                        if (!favoriteLogService.addUrl(userCode, (userInfo, favoriteLog) -> {
                            favoriteLog.setUserInfoId(userInfo.getId());
                            favoriteLog.setUrl(favoriteUrl);
                            favoriteLog.setDocId(docId);