return "zero";
  }

  @Override
  protected Collection<Integer> getValueNotInPopulatedMap() throws UnsupportedOperationException {
    return Lists.newArrayList(0);
  }

  /**
   * The version of this test supplied by {@link MapInterfaceTest} fails for this particular Map
   * implementation, because {@code map.get()} returns a view collection that changes in the course

import java.util.Collection;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import org.jspecify.annotations.Nullable;

/**
 * A {@link BlockingQueue} which forwards all its method calls to another {@link BlockingQueue}.
 * Subclasses should override one or more methods to modify the behavior of the backing collection

        return true;
      }
    }
    return false;
  }

  @Override
  public boolean removeAll(Collection<?> c) {
    return Iterables.removeIf(
        multimap.unfiltered().entries(),
        and(multimap.entryPredicate(), valuePredicateOnEntries(in(c))));
  }

  @Override
  public boolean retainAll(Collection<?> c) {
    return Iterables.removeIf(
        multimap.unfiltered().entries(),

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.core.collection;

import static org.codelibs.core.collection.CollectionsUtil.newArrayList;
import static org.codelibs.core.collection.IndexedIterator.indexed;
import static org.codelibs.core.io.LineIterator.iterable;
import static org.hamcrest.CoreMatchers.is;

 * but reduces variability and avoids starvation.
 *
 * <p>This class and its iterator implement all of the optional methods of the {@link
 * Collection} and {@link Iterator} interfaces.
 *
 * @author Doug Lea
 * @author Justin T. Sampson
 * @param <E> the type of elements held in this collection
 */
// TODO(kak): consider removing some of the @CanIgnoreReturnValue annotations as appropriate
@NullUnmarked

    /**
     * Test method for
     * {@link org.codelibs.core.collection.EmptyIterator#EmptyIterator()}.
     */
    @Test
    public void testEmptyIterator() {
        final EmptyIterator<String> emptyIterator = new EmptyIterator<String>();
        assertThat(emptyIterator, is(notNullValue()));
    }

    /**
     * Test method for {@link org.codelibs.core.collection.EmptyIterator#remove()}
     * .
     */
    @Test

import com.google.common.collect.testing.features.CollectionSize;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Generator for collection of a particular size.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked

 * governing permissions and limitations under the License.
 */
package org.codelibs.core.misc;

import static org.codelibs.core.collection.ArrayUtil.asArray;

import java.util.Collection;
import java.util.Map;

import org.codelibs.core.collection.ArrayUtil;
import org.codelibs.core.exception.ClIllegalArgumentException;
import org.codelibs.core.exception.ClIllegalStateException;

import static java.util.Collections.singletonList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Iterators;
import com.google.common.collect.Multimap;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

import java.util.Collection;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates collections, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public interface TestCollectionGenerator<E extends @Nullable Object>