@MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllAbsentKey() {
    assertEmpty(multimap().removeAll(k3()));
    expectUnchanged();
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllPresentKey() {
    assertContentsAnyOrder(multimap().removeAll(k0()), v0());
    expectMissing(e0());
  }

  @CollectionSize.Require(absent = ZERO)

        public Iterator<K> iterator() {
          return Iterators.unmodifiableIterator(delegate.keySet().iterator());
        }

        @Override
        public boolean removeAll(Collection<?> c) {
          return delegate.keySet().removeAll(c);
        }

        @Override
        public boolean retainAll(Collection<?> c) {
          return delegate.keySet().retainAll(c);
        }
      };
    }

    assertFalse(
        "removeAll(emptyCollection) should return false",
        collection.removeAll(MinimalCollection.of()));
    expectUnchanged();
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAll_nonePresent() {
    assertFalse(
        "removeAll(disjointCollection) should return false",
        collection.removeAll(MinimalCollection.of(e3())));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllAbsentKey() {
    assertEmpty(multimap().removeAll(k3()));
    expectUnchanged();
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllPresentKey() {
    assertContentsAnyOrder(multimap().removeAll(k0()), v0());
    expectMissing(e0());
  }

  @CollectionSize.Require(absent = ZERO)

    }
  }

  @Override
  public boolean containsKey(@CheckForNull Object key) {
    return asMap().get(key) != null;
  }

  @Override
  public Collection<V> removeAll(@CheckForNull Object key) {
    return MoreObjects.firstNonNull(asMap().remove(key), unmodifiableEmptyCollection());
  }

  Collection<V> unmodifiableEmptyCollection() {

    @Deprecated
    public void overwriteActiveProjects(List<String> activeProjectSelectors) {
        List<ProjectActivationSettings> projects = getProjects(pa -> pa.active).collect(Collectors.toList());
        this.activations.removeAll(projects);
        activeProjectSelectors.forEach(this::activateOptionalProject);
    }

    /**
     * Overwrites the inactive projects based on a pre-Maven 4 "inactive projects" list.

    }

    @Override
    public boolean remove(final Object o) {
        return parent.remove(o);
    }

    @Override
    public boolean removeAll(final Collection<?> c) {
        return parent.removeAll(c);
    }

    @Override
    public boolean retainAll(final Collection<?> c) {
        return parent.retainAll(c);
    }

    @Override

  }

  /** Confirm that removeAll() returns a List implementing RandomAccess. */
  public void testRemoveAllRandomAccess() {
    Multimap<String, Integer> multimap = create();
    multimap.put("foo", 1);
    multimap.put("foo", 3);
    assertTrue(multimap.removeAll("foo") instanceof RandomAccess);
    assertTrue(multimap.removeAll("bar") instanceof RandomAccess);
  }

  }

  @Override
  public void testEntrySetRemoveAllNullFromEmpty() {
    try {
      super.testEntrySetRemoveAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().removeAll(null) doesn't throws NPE.
    }
  }

  @Override
  public void testEntrySetRetainAllNullFromEmpty() {
    try {
      super.testEntrySetRetainAllNullFromEmpty();
    } catch (RuntimeException tolerated) {

    } catch (UnsupportedOperationException expected) {
    }
    assertMultimapRemainsUnmodified(multimap, originalEntries);

    // Test #removeAll()
    try {
      multimap.removeAll(sampleKey);
      fail("removeAll succeeded on unmodifiable multimap");
    } catch (UnsupportedOperationException expected) {
    }
    assertMultimapRemainsUnmodified(multimap, originalEntries);