/**
     * Creates and returns a new instance of {@link ConcurrentHashMap}.
     *
     * @param <K> the key type of {@link ConcurrentHashMap}
     * @param <V> the value type of {@link ConcurrentHashMap}
     * @return a new instance of {@link ConcurrentHashMap}
     * @see ConcurrentHashMap#ConcurrentHashMap()
     */
    public static <K, V> ConcurrentHashMap<K, V> newConcurrentHashMap() {
        return new ConcurrentHashMap<>();

 */
public class LeaseManager {

    private static final Logger log = LoggerFactory.getLogger(LeaseManager.class);

    private final ConcurrentHashMap<Smb2LeaseKey, LeaseEntry> leases;
    private final ConcurrentHashMap<String, Smb2LeaseKey> pathToLease;
    private final ConcurrentHashMap<String, WeakReference<SmbFile>> fileCache;
    private final ReadWriteLock lock;
    private final CIFSContext context;

    // GWT's ConcurrentHashMap is a wrapper around HashMap, but it rejects null keys, which matches
    // the behaviour of the non-GWT implementation of newConcurrentHashSet().
    // On the other hand HashSet might be better for code size if apps aren't
    // already using Collections.newSetFromMap and ConcurrentHashMap.
    return Collections.newSetFromMap(new ConcurrentHashMap<E, Boolean>());
  }

        val rootBuildDir: DirectoryProperty
    }

    private val projectStates: ConcurrentHashMap<String, TestFilesCleanupProjectState> = ConcurrentHashMap()

    /**
     * Key is the path of a task, value is the possible report dirs it generates.
     */
    private val taskPathToReports: ConcurrentHashMap<String, List<ReportLocation>> = ConcurrentHashMap()

    /**
     * @see ReportLocation.resolve
     */
    @Volatile

  private final OkHttpClient client;
  private final Set<HttpUrl> fetchedUrls = Collections.synchronizedSet(new LinkedHashSet<>());
  private final BlockingQueue<HttpUrl> queue;
  private final ConcurrentHashMap<String, AtomicInteger> hostnames = new ConcurrentHashMap<>();
  private final int hostLimit;

  public Crawler(OkHttpClient client, int queueLimit, int hostLimit) {
    this.client = client;
    this.queue = new LinkedBlockingQueue<>(queueLimit);

    private final TypeRegistry typeRegistry;

    private final ConcurrentHashMap<String, ArtifactHandler> allHandlers;

    @Inject
    public DefaultArtifactHandlerManager(TypeRegistry typeRegistry) {
        this.typeRegistry = requireNonNull(typeRegistry, "null typeRegistry");
        this.allHandlers = new ConcurrentHashMap<>();
    }

    @Override
    public void onEvent(Object event) {

    private final InetAddress witnessServer;
    private final int port;
    private final CIFSContext context;
    private final ConcurrentHashMap<String, WitnessRegistration> registrations;
    private final ConcurrentHashMap<String, WitnessNotificationListener> listeners;
    private final ConcurrentHashMap<String, CompletableFuture<Void>> asyncNotifyTasks;
    private final ScheduledExecutorService scheduler;

    private static final int MAX_BACKOFF_SHIFT = 3; // Maximum 8 seconds (2^3 * 1000ms)

    private final DirectoryLeaseManager leaseManager;
    private final ConcurrentHashMap<String, ChangeNotificationHandle> activeWatchers;
    private final ConcurrentHashMap<String, Integer> failureCounts;

    /**
     * Directory change types
     */
    public enum DirectoryChangeType {
        /**

  private static final String TEST_KEY = "test key";
  private static final String TEST_VALUE = "test value";

  // Non-loading versions:
  private final Map<Object, Object> map = new MapMaker().makeMap(); // Returns ConcurrentHashMap
  private final Cache<Object, Object> cache = CacheBuilder.newBuilder().recordStats().build();
  private final Cache<Object, Object> cacheNoStats = CacheBuilder.newBuilder().build();

  @BeforeExperiment
  void setUp() {

package org.apache.maven.internal.impl;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.maven.api.JavaPathType;
import org.apache.maven.api.Type;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.services.LanguageRegistry;