* </ol>
   *
   * @param collection the presumed-immutable collection
   * @param sampleElement an element of the same type as that contained by {@code collection}.
   *     {@code collection} may or may not have {@code sampleElement} as a member.
   */
  public static <E extends @Nullable Object> void assertCollectionIsUnmodifiable(
      Collection<E> collection, E sampleElement) {
    Collection<E> siblingCollection = new ArrayList<>();

    // "<String>" is required to work around a javac 1.5 bug.
    Collection<String> c = MinimalCollection.<String>of();
    Set<String> set = copyOf(c);
    assertEquals(Collections.<String>emptySet(), set);
    assertSame(this.<String>of(), set);
  }

  public void testCopyOf_collection_oneElement() {
    Collection<String> c = MinimalCollection.of("a");
    Set<String> set = copyOf(c);

     * @since 3.5.0
     * @deprecated Use {@link #DefaultProjectDependencyGraph(Collection, Collection)} instead.
     */
    @Deprecated
    public DefaultProjectDependencyGraph(List<MavenProject> allProjects, Collection<MavenProject> projects)
            throws CycleDetectedException, DuplicateProjectException {
        this((Collection<MavenProject>) allProjects, projects);
    }

    /**

import java.util.Collection;

public final class Collections2FilterArrayListTest
    extends AbstractFilteredCollectionTest<Collection<Integer>> {
  @Override
  Collection<Integer> createUnfiltered(Iterable<Integer> contents) {
    return Lists.newArrayList(contents);
  }

  @Override
  Collection<Integer> filter(Collection<Integer> elements, Predicate<? super Integer> predicate) {

  public void testEntrySetEquals() {
    resetContainer(mapEntry(k0(), v0()), mapEntry(k1(), v0()), mapEntry(k0(), v3()));
    Set<Entry<K, Collection<V>>> expected = newHashSet();
    expected.add(mapEntry(k0(), (Collection<V>) newHashSet(v0(), v3())));
    expected.add(mapEntry(k1(), (Collection<V>) newHashSet(v0())));
    new EqualsTester().addEqualityGroup(expected, multimap().asMap().entrySet()).testEquals();
  }

   *     to primitives
   * @throws NullPointerException if {@code collection} or any of its elements is null
   */
  public static char[] toArray(Collection<Character> collection) {
    if (collection instanceof CharArrayAsList) {
      return ((CharArrayAsList) collection).toCharArray();
    }

    Object[] boxedArray = collection.toArray();
    int len = boxedArray.length;

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.internal.impl;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

class Graph {
    private enum DfsState {

    @Override
    public Entry<K, Collection<V>>[] createArray(int length) {
      return (Entry<K, Collection<V>>[]) new Entry<?, ?>[length];
    }

    @Override
    public Iterable<Entry<K, Collection<V>>> order(List<Entry<K, Collection<V>>> insertionOrder) {
      Map<K, Collection<V>> map = new HashMap<>();
      List<Entry<K, V>> builder = new ArrayList<>();
      for (Entry<K, Collection<V>> entry : insertionOrder) {

            }
        }

        return artifact;
    }

    @Override
    public Collection<? extends Metadata> finish(Collection<? extends Artifact> artifacts) {
        return Collections.emptyList();
    }

   * @since 8.0
   */
  public <E extends T> List<E> leastOf(Iterable<E> iterable, int k) {
    if (iterable instanceof Collection) {
      Collection<E> collection = (Collection<E>) iterable;
      if (collection.size() <= 2L * k) {
        // In this case, just dumping the collection to an array and sorting is
        // faster than using the implementation for Iterator, which is
        // specialized for k much smaller than n.