### Exception Hierarchy

```
CrawlerSystemException (unchecked)  # Setup/config errors
CrawlingAccessException (checked)   # Runtime crawl errors
  ├─ MaxLengthExceededException
  └─ ChildUrlsException
ExtractException (checked)          # Extraction failures
  └─ UnsupportedExtractException
```

### Thread-Local Storage

```java
// Set (in CrawlerThread)

    @Override
    public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {}
  }

  /**
   * A CyclicBarrier that uses timed await and fails with AssertionFailedErrors instead of throwing
   * checked exceptions.
   */
  public class CheckedBarrier extends CyclicBarrier {
    public CheckedBarrier(int parties) {
      super(parties);
    }

    @Override
    public int await() {

     * indicating that the URL should not be crawled. Otherwise, it returns {@code true}.
     *
     * @param paramMap the parameter map containing potential exclusion patterns
     * @param url the URL to be checked for crawlability
     * @return {@code true} if the URL is crawlable; {@code false} if it matches the exclusion pattern
     */
    protected boolean isUrlCrawlable(final DataStoreParams paramMap, final String url) {

- Kube-proxy: Checked whether IPv6 was available on Linux before using it. ([#131265](https://github.com/kubernetes/kubernetes/pull/131265), [@rikatz](https://github.com/rikatz))

      - kubelet_imagemanager_ondisk_pulledrecords - the number of image pulled records currently kept on disk
      - kubelet_imagemanager_image_mustpull_checks_total{result} - the number for how many times an image was checked against the pull records and the results of those checks ([#132812](https://github.com/kubernetes/kubernetes/pull/132812), [@stlaz](https://github.com/stlaz)) [SIG Auth and Node]