* world. Figure out what sort of space-time tradeoff we're actually going to get here with the
   * *Map variants. This class is particularly hard to benchmark, because the benefit is not only in
   * less allocation, but also having the GC do less work to scan the heap because of fewer
   * references, which is particularly hard to quantify.
   */

  /** Creates an empty {@code CompactHashMap} instance. */

   * the result is chosen uniformly at random in [0, numBits), and then the result is chosen in that
   * range uniformly at random. Zero is treated as having log2 == 0.
   */
  static BigInteger randomNonNegativeBigInteger(int numBits) {
    int digits = RANDOM_SOURCE.nextInt(numBits);
    if (digits == 0) {
      return new BigInteger(1, RANDOM_SOURCE);
    } else {

public interface LegacySupport {

    /**
     * Sets the currently active session. Some legacy components are basically stateful and their API is missing
     * parameters that would be required to delegate to a stateless component. Saving the session (in a thread-local
     * variable) is our best effort to record any state that is required to enable proper delegation.
     *
     * @param session The currently active session, may be {@code null}.
     */

   * {@code null}!) before returning it to callers. Depending on how the code is structured, a
   * nullness analysis might not understand that the field has been populated. To avoid that problem
   * without having to add {@code @SuppressWarnings}, the code can call this method.
   *
   * <p>Why <i>not</i> just add {@code SuppressWarnings}? The problem is that this method is

  private final Set<Type> visited = Sets.newHashSet();

  /**
   * Visits the given types. Null types are ignored. This allows subclasses to call {@code
   * visit(parameterizedType.getOwnerType())} safely without having to check nulls.
   */
  public final void visit(@Nullable Type... types) {
    for (Type type : types) {
      if (type == null || !visited.add(type)) {
        // null owner type, or already visited;
        continue;

 *       #contains}.
 *   <li>Terminology note: a range {@code a} is said to be the <i>maximal</i> range having property
 *       <i>P</i> if, for all ranges {@code b} also having property <i>P</i>, {@code a.encloses(b)}.
 *       Likewise, {@code a} is <i>minimal</i> when {@code b.encloses(a)} for all {@code b} having
 *       property <i>P</i>. See, for example, the definition of {@link #intersection intersection}.

       * FinalizableReference's class loader was reclaimed. While there's a chance that other
       * finalizable references could be enqueued subsequently (at which point the class loader
       * would be resurrected by virtue of us having a strong reference to it), we should pretty
       * much just shut down and make sure we don't keep it alive any longer than necessary.
       */
      return null;
    }
    try {

import java.lang.reflect.Method;
import java.util.Locale;
import junit.framework.TestCase;

/**
 * Since annotations have some reusability issues that force copy and paste all over the place, it's
 * worth having a test to ensure that all our Feature enums have their annotations correctly set up.
 *
 * @author George van den Driessche
 */
public class FeatureEnumTest extends TestCase {

 *     .test();
 * }</pre>
 *
 * <p>Note that testing {@link Object#equals(Object)} is more simply done using the {@link
 * EqualsTester}. It includes an extra test against an instance of an arbitrary class without having
 * to explicitly add another equivalence group.
 *
 * @author Gregory Kick
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class EquivalenceTester<T> {

        // snapshot timestamp, or some other timestamp later encoded into the metadata.
        // TODO this needs to be repeated here so the merging doesn't interfere with the written metadata
        //  - we'd be much better having a pristine input, and an ongoing metadata for merging instead

        Map<ArtifactRepository, Metadata> previousMetadata = new HashMap<>();
        ArtifactRepository selected = null;