public final <C extends Collection<? super E>> C copyInto(C collection) {
    checkNotNull(collection);
    Iterable<E> iterable = getDelegate();
    if (iterable instanceof Collection) {
      collection.addAll((Collection<E>) iterable);
    } else {
      for (E item : iterable) {
        collection.add(item);
      }
    }
    return collection;
  }

  /**

import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.testing.SerializableTester;
import org.junit.Ignore;

/**
 * Basic reserialization test for collections.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")

      checkNotNull(elements);
      if (elements instanceof Collection) {
        Collection<?> collection = (Collection<?>) elements;
        ensureRoomFor(collection.size());
        if (collection instanceof ImmutableCollection) {
          ImmutableCollection<?> immutableCollection = (ImmutableCollection<?>) collection;
          size = immutableCollection.copyIntoArray(contents, size);
          return this;

        .createTestSuite();
  }

  static class ElementSetGenerator<E> implements TestSetGenerator<E> {
    final OneSizeTestContainerGenerator<Collection<E>, E> gen;

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

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

    @Override

    return getList().size() / 2;
  }

  /**
   * Returns the {@link java.lang.reflect.Method} instance for {@link #testSet_null()} so that tests
   * of {@link java.util.Collections#checkedCollection(java.util.Collection, Class)} can suppress it
   * with {@code FeatureSpecificTestSuiteBuilder.suppressing()} until <a
   * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6409434">Sun bug 6409434</a> is fixed.

   * collection in unspecified order.
   *
   * @param collection the elements that the set should contain
   * @return a new {@code CompactHashSet} containing those elements (minus duplicates)
   */
  public static <E extends @Nullable Object> CompactHashSet<E> create(
      Collection<? extends E> collection) {
    CompactHashSet<E> set = createWithExpectedSize(collection.size());
    set.addAll(collection);

import static com.google.common.collect.testing.features.ListFeature.SUPPORTS_ADD_WITH_INDEX;
import static com.google.common.collect.testing.testers.ReflectionFreeAssertThrows.assertThrows;
import static java.util.Collections.singletonList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.MinimalCollection;
import com.google.common.collect.testing.features.CollectionFeature;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.io.File;
import java.net.MalformedURLException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Random;
import java.util.Set;
import java.util.TreeMap;
import java.util.stream.Collectors;

 */
package org.apache.maven.graph;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.maven.MavenExecutionException;

import com.google.j2objc.annotations.Weak;
import com.google.j2objc.annotations.WeakOuter;
import java.util.AbstractQueue;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.PriorityQueue;