while (true) {
      AtomicInteger existingCounter = safeGet(countMap, element);
      if (existingCounter == null) {
        existingCounter = countMap.putIfAbsent(element, new AtomicInteger(occurrences));
        if (existingCounter == null) {
          return 0;
        }
        // existingCounter != null: fall through to operate against the existing AtomicInteger
      }

 */
package org.codelibs.core.beans.factory;

import static org.codelibs.core.collection.CollectionsUtil.newConcurrentHashMap;
import static org.codelibs.core.collection.CollectionsUtil.putIfAbsent;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.util.concurrent.ConcurrentMap;

import org.codelibs.core.beans.BeanDesc;
import org.codelibs.core.beans.impl.BeanDescImpl;

    }
  }

  public void testPutIfAbsent() {
    TestMap map = new TestMap();
    map.put("foo", 1);
    assertEquals(Integer.valueOf(1), map.putIfAbsent("foo", 2));
    assertEquals(Integer.valueOf(1), map.get("foo"));
    assertThat(map.putIfAbsent("bar", 3)).isNull();
    assertEquals(Integer.valueOf(3), map.get("bar"));
  }

  public void testRemove() {
    TestMap map = new TestMap();
    map.put("foo", 1);

  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);
  }

    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);

    @Override
    public void replaceAll(final BiFunction<? super K, ? super V, ? extends V> function) {
        parent.replaceAll(function);
    }

    @Override
    public V putIfAbsent(final K key, final V value) {
        return parent.putIfAbsent(key, value);
    }

    @Override
    public boolean remove(final Object key, final Object value) {
        if (parent.remove(key, value)) {
            return true;

                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(

            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));
    }

            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) {

   *
   * <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.
   *