}

      @Override
      int maxSize() {
        return maxSize(set1);
      }
    };
  }

  /**
   * Returns an unmodifiable <b>view</b> of the symmetric difference of two sets. The returned set
   * contains all elements that are contained in either {@code set1} or {@code set2} but not in
   * both. The iteration order of the returned set is undefined.
   *

        assertTrue(item1.equals(item4));

        // Null object
        assertFalse(item1.equals(null));

        // Different class
        assertFalse(item1.equals("word"));

        // Symmetry
        assertTrue(item1.equals(item2));
        assertTrue(item2.equals(item1));
    }

    public void test_equals_withNullInput() {
        // Test equals with null input

        CharMappingItem item4 = new CharMappingItem(4L, inputs1, "different");

        // Test reflexivity
        assertTrue(item1.equals(item1));

        // Test symmetry and arrays with different order
        assertTrue(item1.equals(item2));
        assertTrue(item2.equals(item1));

        // Test with different inputs
        assertFalse(item1.equals(item3));

   * {@link TypeVariableImpl#equals(Object)} is changed to no longer be equal to custom TypeVariable
   * implementations. As a result, we need to make sure our TypeVariable implementation respects
   * symmetry. Moreover, we don't want to reconstruct a native type variable {@code <A>} using our
   * implementation unless some of its bounds have changed in resolution. This avoids creating

   * {@link TypeVariableImpl#equals(Object)} is changed to no longer be equal to custom TypeVariable
   * implementations. As a result, we need to make sure our TypeVariable implementation respects
   * symmetry. Moreover, we don't want to reconstruct a native type variable {@code <A>} using our
   * implementation unless some of its bounds have changed in resolution. This avoids creating

    }

    @Override
    public boolean equals(@Nullable Object obj) {
      // In general getClass().isInstance() is bad for equals.
      // But here we fully control the subclasses to ensure symmetry.
      if (getClass().isInstance(obj)) {
        Wrapper that = (Wrapper) obj;
        return wrapped.equals(that.wrapped);
      }
      return false;
    }

    @Override