crawler2.getCrawlerContext().setNumOfThread(numOfThread);

            final String sessionId1 = crawler1.execute();
            final String sessionId2 = crawler2.execute();

            assertNotSame(sessionId1, sessionId2);
            assertNotSame(crawler1.crawlerContext, crawler2.crawlerContext);

            // Wait for both crawlers to start with polling

        assertArrayEquals(testKey, rawKey2, "Should still match original");
    }

    @Test
    public void testRemoveSessionKey() {
        String sessionId = "test-session-3";
        keyManager.storeSessionKey(sessionId, testKey, "AES");

        assertTrue(keyManager.hasSessionKey(sessionId), "Key should exist");

        keyManager.removeSessionKey(sessionId);

crawler2.setSessionId("session2");
crawler2.addUrl("https://site2.com");

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

String sessionId1 = crawler1.execute();
String sessionId2 = crawler2.execute();

crawler1.awaitTermination();
crawler2.awaitTermination();
```

### Custom Interval Control

```java
// Configure politeness policy

     *
     * @param sessionId the session identifier to find the latest crawling parameters for
     * @return a list of CrawlingInfoParam entities from the latest session, or empty list if none found
     */
    public List<CrawlingInfoParam> getLastCrawlingInfoParamList(final String sessionId) {
        final CrawlingInfo crawlingInfo = getLast(sessionId);
        if (crawlingInfo == null) {

    /**
     * Generates URL queues from a previous session's access results.
     * @param previousSessionId The previous session ID.
     * @param sessionId The current session ID.
     */
    @Override
    public void generateUrlQueues(final String previousSessionId, final String sessionId) {
        final Queue<UrlQueueImpl<Long>> urlQueueList = dataHelper.getUrlQueueList(sessionId);

     *
     * @param sessionId the session ID
     * @return the count of access results
     */
    @Override
    public int getCount(final String sessionId) {
        return dataHelper.getAccessResultMap(sessionId).size();
    }

    /**
     * Deletes all access results for the specified session.
     *
     * @param sessionId the session ID
     */
    @Override

     * @param sessionId the session ID
     * @return the URL queue for the session
     */
    public synchronized Queue<UrlQueueImpl<Long>> getUrlQueueList(final String sessionId) {
        Queue<UrlQueueImpl<Long>> urlQueueList = urlQueueMap.get(sessionId);
        if (urlQueueList == null) {
            urlQueueList = new LinkedList<>();
            urlQueueMap.put(sessionId, urlQueueList);
        }

     *
     * @param sessionId the session ID to process
     * @return the canonical session ID (portion before first hyphen, or original if no hyphen)
     */
    public String getCanonicalSessionId(final String sessionId) {
        final int idx = sessionId.indexOf('-');
        if (idx >= 0) {
            return sessionId.substring(0, idx);
        }
        return sessionId;
    }

    /**

     *
     * @param sessionId the session ID whose data should be deleted
     */
    private void deleteBySessionId(final String sessionId) {
        try {
            urlFilterService.delete(sessionId);
        } catch (final Exception e) {
            logger.warn("Failed to delete url filters: {}", sessionId, e);
        }
        try {

        // Generate unique session ID for key management
        this.sessionId = String.format("smb-enc-%d-%d", System.currentTimeMillis(), secureRandom.nextLong());

        if (keyManager != null) {
            // Store keys securely
            String encKeyId = sessionId + "-enc";
            String decKeyId = sessionId + "-dec";
            keyManager.storeSessionKey(encKeyId, encryptionKey, "AES");