static boolean removeAllImpl(Multiset<?> self, Collection<?> elementsToRemove) {
    Collection<?> collection =
        (elementsToRemove instanceof Multiset)
            ? ((Multiset<?>) elementsToRemove).elementSet()
            : elementsToRemove;

    return self.elementSet().removeAll(collection);
  }

  /** An implementation of {@link Multiset#retainAll}. */

      // Only trust the size of `values` if it is a Set and therefore probably already deduplicated.
      if (values instanceof Set<?>) {
        Set<?> collection = (Set<?>) values;
        return max(defaultExpectedValues, collection.size());
      } else {
        return defaultExpectedValues;
      }
    }

    /**
     * {@inheritDoc}
     *

    public static final String CONTAINS = "contains:";

    /** XML element name for collections container. */
    protected static final String COLLECTIONS = "collections";

    /** XML element name for individual collection. */
    protected static final String COLLECTION = "collection";

    /** XML element name for global parameters container. */

        return mainArtifact.flatMap(artifactManager::getPath);
    }

    @Nonnull
    @Override
    public Collection<ProducedArtifact> getAttachedArtifacts(@Nonnull Project project) {
        requireNonNull(project, "project" + " cannot be null");
        Collection<ProducedArtifact> attached =
                map(getMavenProject(project).getAttachedArtifacts(), a -> getSession(project)

    /**
     * Transform Graph into a Collection of metadata objects that
     * could serve as a classpath for a particular scope
     *
     * @param dirtyGraph - dependency graph
     * @param scope - which classpath to extract
     * @param resolve - whether to resolve artifacts.
     * @return Collection of metadata objects in the linked subgraph of the graph which

    return new OpenJdk6SetTests().allTests();
  }

  @Override
  protected Collection<Method> suppressForTreeSetNatural() {
    return asList(
        getAddNullUnsupportedMethod(),
        getAddAllNullUnsupportedMethod(),
        getCreateWithNullUnsupportedMethod());
  }

  @Override
  protected Collection<Method> suppressForCheckedSet() {

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.services;

import java.util.Collection;
import java.util.Collections;

import org.apache.maven.api.ProducedArtifact;
import org.apache.maven.api.Service;
import org.apache.maven.api.Session;
import org.apache.maven.api.annotations.Experimental;

    /**
     * Returns the element type if the parameter type of the method is a parameterized {@link Collection}.
     *
     * @param index
     *            The index of the parameter
     * @return The element type if the parameter type is a parameterized {@link Collection}, otherwise {@literal null}
     */
    Class<?> getElementClassOfCollection(int index);

    /**

    }
    return derivedSuites;
  }

  private static final class ReserializedListGenerator<E> implements TestListGenerator<E> {
    final OneSizeTestContainerGenerator<Collection<E>, E> gen;

    private ReserializedListGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen) {
      this.gen = gen;
    }

    @Override
    public SampleElements<E> samples() {
      return gen.samples();
    }

    @Override

   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(Collection<T> collection) {
    // return collection::iterator;
    return new Iterable<T>() {
      @Override
      public Iterator<T> iterator() {
        return collection.iterator();
      }
    };
  }

  public void testEquals() {
    new EqualsTester()