return unmodifiableCollectionSubclass(createCollection());
  }

  /**
   * Creates the collection of values for a single key.
   *
   * <p>Collections with weak, soft, or phantom references are not supported. Each call to {@code
   * createCollection} should create a new instance.
   *
   * <p>The returned collection class determines whether duplicate key-value pairs are allowed.
   *

    assertTrue(queue.add("hi"));
    assertEquals("hi", queue.element());
    assertEquals("hi", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());

    assertTrue(queue.add("there"));
    assertEquals("there", queue.element());
    assertEquals("there", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());

    assertEquals(20, spec.maximumSize.intValue());
    assertNull(spec.maximumWeight);
    assertEquals(30, spec.concurrencyLevel.intValue());
    assertEquals(Strength.WEAK, spec.keyStrength);
    assertEquals(Strength.WEAK, spec.valueStrength);
    assertEquals(TimeUnit.HOURS, spec.writeExpirationTimeUnit);
    assertEquals(TimeUnit.MINUTES, spec.accessExpirationTimeUnit);

  }

  public void testWeak_builder() {
    int concurrencyLevel = 42;
    Interner<Object> interner =
        Interners.newBuilder().weak().concurrencyLevel(concurrencyLevel).build();
    InternerImpl<Object> internerImpl = (InternerImpl<Object>) interner;
    assertEquals(Strength.WEAK, internerImpl.map.keyStrength());
    assertEquals(concurrencyLevel, internerImpl.map.concurrencyLevel);
  }

 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.MapMakerInternalMap.Strength.STRONG;
import static com.google.common.collect.MapMakerInternalMap.Strength.WEAK;
import static com.google.common.testing.SerializableTester.reserializeAndAssert;
import static java.util.Arrays.asList;
import static org.junit.Assert.assertThrows;
import static org.mockito.ArgumentMatchers.isA;

  }

  public void testGetIfPresent_whenNoMatchingConstant() {
    assertThat(Enums.getIfPresent(TestEnum.class, "WOMBAT")).isAbsent();
  }


  @J2ktIncompatible
  @GwtIncompatible // weak references
  @AndroidIncompatible // depends on details of GC and classloading
  public void testGetIfPresent_doesNotPreventClassUnloading() throws Exception {
    WeakReference<?> shadowLoaderReference = doTestClassUnloading();

   *     Iterators.peekingIterator(Iterators.forArray("a", "b"));
   * String a1 = peekingIterator.peek(); // returns "a"
   * String a2 = peekingIterator.peek(); // also returns "a"
   * String a3 = peekingIterator.next(); // also returns "a"
   * }</pre>
   *
   * <p>Any structural changes to the underlying iteration (aside from those performed by the

import static com.google.common.collect.NullnessCasts.uncheckedCastNullableTToT;
import static java.lang.Math.max;

import com.google.common.annotations.GwtCompatible;
import com.google.j2objc.annotations.Weak;
import java.util.Comparator;
import java.util.Spliterator;
import java.util.function.Consumer;
import java.util.function.DoubleConsumer;
import java.util.function.Function;
import java.util.function.IntConsumer;

      this.queue = new ArrayDeque<>();
      queue.add(root);
    }

    @Override
    public boolean hasNext() {
      return !queue.isEmpty();
    }

    @Override
    public T peek() {
      return queue.element();
    }

    @Override
    public T next() {
      T result = queue.remove();
      Iterables.addAll(queue, children(result));
      return result;
    }
  }

   */
  private boolean finalizeReference(Reference<?> reference, Method finalizeReferentMethod) {
    /*
     * This is for the benefit of phantom references. Weak and soft references will have already
     * been cleared by this point.
     */
    reference.clear();

    if (reference == frqReference) {
      /*