Set<Throwable> seenExceptionsLocal = seenExceptions;
    if (seenExceptionsLocal == null) {
      // TODO(cpovirk): Should we use a simpler (presumably cheaper) data structure?
      /*
       * Using weak references here could let us release exceptions earlier, but:
       *
       * 1. On Android, querying a WeakReference blocks if the GC is doing an otherwise-concurrent
       * pass.
       *

    /**
     * Gets the problems that were encountered during the settings building. Note that only problems of severity
     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link ToolchainsBuilderException}.
     *

 * specified for this filter. The wildcard has no influence on this
 * method as the server should have performed that filtering already. The
 * attributes are asserted here only because server file systems may not
 * support filtering by all attributes (e.g. even though ATTR_DIRECTORY was
 * specified the server may still return objects that are not directories).
 */

    static String getMessageByCode( int errcode ) {
        /* Note there's a signedness error here because 0xC0000000 based values are
         * negative so it with NT_STATUS_SUCCESS (0) the binary search will not be
         * performed properly. The effect is that the code at index 1 is never found
         * (NT_STATUS_UNSUCCESSFUL). So here we factor out NT_STATUS_SUCCESS
         * as a special case (which it is).
         */

            // The root locator can be used very early during the setup of Maven,
            // even before the arguments from the command line are parsed.  Any exception
            // that would happen here should cause the build to fail at a later stage
            // (when actually parsing the POM) and will lead to a better exception being
            // displayed to the user, so just bail out and return false.
        }

      collection.clear();
      iterator.next();
      /*
       * We prefer for iterators to fail immediately on hasNext, but ArrayList
       * and LinkedList will notably return true on hasNext here!
       */
      fail("Expected ConcurrentModificationException");
    } catch (ConcurrentModificationException expected) {
      // success
    }
  }

     * didn't see that discussed in the review, which included many other
     * changes: http://goo.gl/okTTdr
     *
     * TODO(cpovirk): decide what the best long-term action here is: force users
     * to suppress (as we do now), stop testing entrySet().add() at all, make
     * entrySet().add() tests tolerant of either behavior, introduce a map

        }
    }

    @Override
    public void artifactDescriptorInvalid(RepositoryEvent event) {
        // The exception stack trace is not really interesting here
        // but the message itself may be quite details and span multiple
        // lines with errors in it, so only display it at debug level.

     * didn't see that discussed in the review, which included many other
     * changes: http://goo.gl/okTTdr
     *
     * TODO(cpovirk): decide what the best long-term action here is: force users
     * to suppress (as we do now), stop testing entrySet().add() at all, make
     * entrySet().add() tests tolerant of either behavior, introduce a map

 * is a thin wrapper around {@link InetAddresses} and {@link InternetDomainName}; the unit tests for
 * those classes explore numerous corner cases. The intent here is to confirm that everything is
 * wired up properly.
 *
 * @author Craig Berry
 */
public final class HostSpecifierTest extends TestCase {

  private static final ImmutableList<String> GOOD_IPS =