public static Equivalence<Object> identity() {
    return Identity.INSTANCE;
  }

  static final class Equals extends Equivalence<Object> implements Serializable {

    static final Equals INSTANCE = new Equals();

    @Override
    protected boolean doEquivalent(Object a, Object b) {
      return a.equals(b);
    }

    @Override
    protected int doHash(Object o) {
      return o.hashCode();
    }

      return g.apply(f.apply(a));
    }

    @Override
    public boolean equals(@CheckForNull Object obj) {
      if (obj instanceof FunctionComposition) {
        FunctionComposition<?, ?, ?> that = (FunctionComposition<?, ?, ?>) obj;
        return f.equals(that.f) && g.equals(that.g);
      }
      return false;
    }

    @Override
    public int hashCode() {

      return p.apply(f.apply(a));
    }

    @Override
    public boolean equals(@CheckForNull Object obj) {
      if (obj instanceof CompositionPredicate) {
        CompositionPredicate<?, ?> that = (CompositionPredicate<?, ?>) obj;
        return f.equals(that.f) && p.equals(that.p);
      }
      return false;
    }

    @Override
    public int hashCode() {

    }
  }

  private interface Equals {
    @Override
    boolean equals(@Nullable Object obj);

    @Override
    int hashCode();

    @Override
    String toString();
  }

  private static class NoDelegateToEquals implements Equals {

    private static Function<Equals, Equals> WRAPPER =
        new Function<Equals, Equals>() {
          @Override

        .addEquivalenceGroup(ImmutableList.of("a", "b"), ImmutableList.of("a", "b"))
        .test();
  }

  public void testPairwiseEquivalent_equals() {
    new EqualsTester()
        .addEqualityGroup(Equivalence.equals().pairwise(), Equivalence.equals().pairwise())
        .addEqualityGroup(Equivalence.identity().pairwise())
        .testEquals();
  }

    return delegate().setValue(value);
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    return delegate().equals(object);
  }

  @Override
  public int hashCode() {
    return delegate().hashCode();
  }

  /**
   * A sensible definition of {@link #equals(Object)} in terms of {@link #getKey()} and {@link

      this.delegateString = delegateString;
      this.onHashCode = onHashCode;
      this.onEquals = onEquals;
      this.onCompareTo = onCompareTo;
    }

    @Override
    public int hashCode() {
      onHashCode.run();
      return delegateString.hashCode();
    }

    @Override
    public boolean equals(@Nullable Object other) {
      onEquals.run();

      return g.apply(f.apply(a));
    }

    @Override
    public boolean equals(@CheckForNull Object obj) {
      if (obj instanceof FunctionComposition) {
        FunctionComposition<?, ?, ?> that = (FunctionComposition<?, ?, ?>) obj;
        return f.equals(that.f) && g.equals(that.g);
      }
      return false;
    }

    @Override
    public int hashCode() {

    }

    public void test_equals1() {
        final StemmerOverrideItem stemmerOverrideItem1 = new StemmerOverrideItem(1, "aaa", "a");

        assertTrue(stemmerOverrideItem1.equals(stemmerOverrideItem1));
        assertTrue(stemmerOverrideItem1.equals(new StemmerOverrideItem(1, "aaa", "a")));
        assertTrue(stemmerOverrideItem1.equals(new StemmerOverrideItem(2, "aaa", "a")));

   * equals()} contract.
   *
   * <p><b>Java 7+ users:</b> This method should be treated as deprecated; use {@link
   * java.util.Objects#equals} instead.
   */
  public static boolean equal(@CheckForNull Object a, @CheckForNull Object b) {
    return a == b || (a != null && a.equals(b));
  }

  /**
   * Generates a hash code for multiple values. The hash code is generated by calling {@link