}
      };

  private CacheBuilderFactory factoryWithAllKeyStrengths() {
    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.of(STRONG, Strength.WEAK, Strength.SOFT));
  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();

 *
 * <p>Applications are encouraged to use a {@code CycleDetectingLockFactory} to create any locks for
 * which external/unmanaged code is executed while the lock is held. (See caveats under
 * <strong>Performance</strong>).
 *
 * <p><strong>Cycle Detection</strong>
 *
 * <p>Deadlocks can arise when locks are acquired in an order that forms a cycle. In a simple

    return maker;
  }

  // constructor tests

  public void testDefaults() {
    MapMakerInternalMap<Object, Object, ?, ?> map = makeMap(createMapMaker());

    assertSame(Strength.STRONG, map.keyStrength());
    assertSame(Strength.STRONG, map.valueStrength());
    assertSame(map.keyStrength().defaultEquivalence(), map.keyEquivalence);
    assertSame(map.valueStrength().defaultEquivalence(), map.valueEquivalence());

    return maker;
  }

  // constructor tests

  public void testDefaults() {
    MapMakerInternalMap<Object, Object, ?, ?> map = makeMap(createMapMaker());

    assertSame(Strength.STRONG, map.keyStrength());
    assertSame(Strength.STRONG, map.valueStrength());
    assertSame(map.keyStrength().defaultEquivalence(), map.keyEquivalence);
    assertSame(map.valueStrength().defaultEquivalence(), map.valueEquivalence());

   */
  enum Strength {
    /*
     * TODO(kevinb): If we strongly reference the value and aren't loading, we needn't wrap the
     * value. This could save ~8 bytes per entry.
     */

    STRONG {
      @Override
      Equivalence<Object> defaultEquivalence() {
        return Equivalence.equals();
      }
    },

    SOFT {
      @Override
      Equivalence<Object> defaultEquivalence() {

   * immutable list is returned.)
   *
   * <p><b>Note:</b> in almost all circumstances, the returned {@link ImmutableList} retains a
   * strong reference to {@code this}, which may prevent the original list from being garbage
   * collected. If you want the original list to be eligible for garbage collection, you should
   * create and use a copy of the sub list (e.g., {@code

        if ((p & 1) != 0) {
          res = mulMod(res, a, m);
        }
        a = squareMod(a, m);
      }
      return res;
    }

    /** Returns true if n is a strong probable prime relative to the specified base. */
    private boolean testWitness(long base, long n) {
      int r = Long.numberOfTrailingZeros(n - 1);
      long d = (n - 1) >> r;
      base %= n;

    private final MapMaker mapMaker = new MapMaker();
    private boolean strong = true;

    private InternerBuilder() {}

    /**
     * Instructs the {@link InternerBuilder} to build a strong interner.
     *
     * @see Interners#newStrongInterner()
     */
    public InternerBuilder strong() {
      this.strong = true;
      return this;
    }

    /**

      MapMaker builder) {
    if (builder.getKeyStrength() == Strength.STRONG
        && builder.getValueStrength() == Strength.STRONG) {
      return new MapMakerInternalMap<>(builder, StrongKeyStrongValueEntry.Helper.<K, V>instance());
    }
    if (builder.getKeyStrength() == Strength.STRONG
        && builder.getValueStrength() == Strength.WEAK) {

  }

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

  public void testWeak_simplistic() {
    String canonical = "a";
    String not = new String("a");