protected ForwardingConcurrentMap() {}

  @Override
  protected abstract ConcurrentMap<K, V> delegate();

  @CanIgnoreReturnValue
  @Override
  public @Nullable V putIfAbsent(K key, V value) {
    return delegate().putIfAbsent(key, value);
  }

  @CanIgnoreReturnValue
  @Override
  public boolean remove(@Nullable Object key, @Nullable Object value) {
    return delegate().remove(key, value);
  }

    for (int i = 0; i < ITERATIONS; i++) {
      long before = map.get(key);
      long result = map.putIfAbsent(key, newValue);
      long after = map.get(key);
      assertEquals(before, result);
      assertEquals(before == 0 ? newValue : before, after);

      map.remove(key);
      before = map.get(key);
      result = map.putIfAbsent(key, newValue);
      after = map.get(key);
      assertEquals(0, before);

    }

    private static List<String> visitAll(
            Collection<Vertex> children, Map<Vertex, DfsState> stateMap, List<String> list) {
        for (Vertex v : children) {
            DfsState state = stateMap.putIfAbsent(v, DfsState.VISITING);
            if (state == null) {
                visitAll(v.children, stateMap, list);
                stateMap.put(v, DfsState.VISITED);
                list.add(v.label);
            }
        }

    map.putAll(ImmutableMap.of(two, three));
    assertThat(map.get(two)).isSameInstanceAs(three);
    assertThat(map.putIfAbsent(one, three)).isSameInstanceAs(two);
    assertThat(map.get(one)).isSameInstanceAs(two);
    assertThat(map.putIfAbsent(three, one)).isNull();
    assertThat(map.get(three)).isSameInstanceAs(one);
    assertThat(map.replace(one, three)).isSameInstanceAs(two);

   *
   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values
   * into the cache. Newly loaded values are added to the cache using {@code
   * Cache.asMap().putIfAbsent} after loading has completed; if another value was associated with
   * {@code key} while the new value was loading then a removal notification will be sent for the
   * new value.
   *

                String key = coreExtension.getGroupId() + ":" + coreExtension.getArtifactId();
                CoreExtension conflict = selectedExtensions.putIfAbsent(key, coreExtension);
                if (conflict != null && !Objects.equals(coreExtension.getVersion(), conflict.getVersion())) {
                    conflicts.add(String.format(

            Map<String, DfsState> stateMap,
            LinkedList<String> cycle) {
        if (children != null) {
            for (String v : children) {
                DfsState state = stateMap.putIfAbsent(v, DfsState.VISITING);
                if (state == null) {
                    cycle.addLast(v);
                    List<String> ret = visitCycle(graph, graph.get(v), stateMap, cycle);
                    if (ret != null) {

            if (up.isPresent()) {
                had++;
                for (Map.Entry<String, String> entry : up.get().entrySet()) {
                    items.putIfAbsent(entry.getKey(), entry.getValue());
                }
            }
        }
        return had == 0 ? Optional.empty() : Optional.of(Map.copyOf(items));
    }

   * zero, associate it with {@code newValue}. Returns the previous value associated with {@code
   * key}, or zero if there was no mapping for {@code key}.
   */
  long putIfAbsent(K key, long newValue) {
    AtomicBoolean noValue = new AtomicBoolean(false);
    Long result =
        map.compute(
            key,
            (K k, @Nullable Long oldValue) -> {

        return node1;
    }

    private Map<String, MojoExecution> mergeMojos(Map<String, MojoExecution> l1, Map<String, MojoExecution> l2) {
        l2.forEach(l1::putIfAbsent);
        return l1;
    }

    // gather artifactIds which are not unique so that the respective thread names can be extended with the groupId
    public Set<String> duplicateIds() {