* in {@linkplain WeakReference weak} references.
 *
 * <p>Usage example:
 *
 * {@snippet :
 * ConcurrentMap<Request, Stopwatch> timers = new MapMaker()
 *     .concurrencyLevel(4)
 *     .weakKeys()
 *     .makeMap();
 * }
 *
 * <p>These features are all optional; {@code new MapMaker().makeMap()} returns a valid concurrent
 * map that behaves similarly to a {@link ConcurrentHashMap}.
 *

  private static <K, V>
      MapMakerInternalMap<K, V, ? extends InternalEntry<K, V, ?>, ? extends Segment<K, V, ?, ?>>
          makeMap(MapMaker maker) {
    return MapMakerInternalMap.create(maker);
  }

  private static MapMaker createMapMaker() {
    MapMaker maker = new MapMaker();
    maker.useCustomMap = true;
    return maker;
  }

  // constructor tests

  public void testDefaults() {

  private static <K, V>
      MapMakerInternalMap<K, V, ? extends InternalEntry<K, V, ?>, ? extends Segment<K, V, ?, ?>>
          makeMap(MapMaker maker) {
    return MapMakerInternalMap.create(maker);
  }

  private static MapMaker createMapMaker() {
    MapMaker maker = new MapMaker();
    maker.useCustomMap = true;
    return maker;
  }

  // constructor tests

  public void testDefaults() {

    MapMakerStrongKeysStrongValues {
      @Override
      public <K extends Comparable<K>, V> Map<K, V> create(Map<K, V> map) {
        // We use a "custom" equivalence to force MapMaker to make a MapMakerInternalMap.
        ConcurrentMap<K, V> newMap = new MapMaker().keyEquivalence(Equivalence.equals()).makeMap();
        checkState(newMap instanceof MapMakerInternalMap);
        newMap.putAll(map);
        return newMap;
      }
    },

     */
    final Map<LockGraphNode, ExampleStackTrace> allowedPriorLocks =
        new MapMaker().weakKeys().makeMap();

    /**
     * The map tracking lock nodes that can cause a lock acquisition cycle if acquired before this
     * node.
     */
    final Map<LockGraphNode, PotentialDeadlockException> disallowedPriorLocks =
        new MapMaker().weakKeys().makeMap();

    final String lockName;

       * UnsignedBytesBenchmark. TODO(cpovirk): benchmark this
       */
      /*
       * A CopyOnWriteArraySet<WeakReference> is faster than a newSetFromMap of a MapMaker map with
       * weakKeys() and concurrencyLevel(1), even up to at least 12 cached exception types.
       */
      private static final Set<WeakReference<Class<? extends Exception>>> validClasses =

import com.google.common.base.MoreObjects;
import com.google.common.base.Preconditions;
import com.google.common.base.Supplier;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.MapMaker;
import com.google.common.math.IntMath;
import com.google.common.primitives.Ints;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.math.RoundingMode;

       * UnsignedBytesBenchmark. TODO(cpovirk): benchmark this
       */
      /*
       * A CopyOnWriteArraySet<WeakReference> is faster than a newSetFromMap of a MapMaker map with
       * weakKeys() and concurrencyLevel(1), even up to at least 12 cached exception types.
       */
      private static final Set<WeakReference<Class<? extends Exception>>> validClasses =