* allowing the CAS below to succeed.
     */
    Thread currentThread = Thread.currentThread();
    if (!compareAndSet(null, currentThread)) {
      return; // someone else has run or is running.
    }

    boolean run = !isDone();
    T result = null;
    Throwable error = null;
    try {
      if (run) {
        result = runInterruptibly();

 * @param <V> the type of the cache's values, which are not permitted to be null
 * @author Charles Fry
 * @since 10.0
 */
@DoNotMock("Use CacheBuilder.newBuilder().build()")
@GwtCompatible
public interface Cache<K, V> {

  /**
   * Returns the value associated with {@code key} in this cache, or {@code null} if there is no
   * cached value for {@code key}.
   *

      when (val protocol = sslSocket.applicationProtocol) {
        null, "" -> null
        else -> protocol
      }
    } catch (e: UnsupportedOperationException) {
      // https://docs.oracle.com/javase/9/docs/api/javax/net/ssl/SSLSocket.html#getApplicationProtocol--
      null
    }

  override fun trustManager(sslSocketFactory: SSLSocketFactory): X509TrustManager? {

    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().removeAll(null) doesn't throws NPE.
    }
  }

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

  @Override

     *
     * @param request The repository request from which this cache was retrieved, must not be {@code null}.
     * @param key The key to use associate the data with, must not be {@code null}.
     * @param data The data to store in the cache, may be {@code null}.
     */
    void put(RepositoryRequest request, Object key, Object data);

    /**

     */
    private synchronized void initLifecycleMap() {
        if (lifecycleMap == null) {
            lifecycleMap = new HashMap<>();

            if (lifecycles != null) {
                for (Lifecycle lifecycle : lifecycles) {
                    lifecycleMap.put(lifecycle.getId(), lifecycle);
                }
            } else {

        // Act + Assert
        assertThrows(PACDecodingException.class, () -> new KerberosApRequest(notASequence, null));
    }

    @Test
    @DisplayName("seq ctor: valid minimal sequence sets apOptions and leaves ticket null")
    void sequenceConstructor_minimal_valid_setsApOptions_noTicket() throws Exception {
        // Arrange
        byte ap = (byte) 0x7A;

            getMap()
                .computeIfAbsent(
                    null,
                    k -> {
                      assertNull(k);
                      return v3();
                    }));
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported computeIfAbsent(null, function)");
  }

        if (deploymentTimestamp == null) {
            deploymentTimestamp = getUtcDateFormatter().format(new Date());
        }
        return deploymentTimestamp;
    }

    @Override
    protected String constructVersion(Versioning versioning, String baseVersion) {
        String version = null;
        Snapshot snapshot = versioning.getSnapshot();
        if (snapshot != null) {

        ComponentUtil.getLogNotificationHelper()
                .offer(new LogNotificationEvent(System.currentTimeMillis(), "ERROR", "org.test", "msg1", null));
        ComponentUtil.getLogNotificationHelper()
                .offer(new LogNotificationEvent(System.currentTimeMillis(), "WARN", "org.test", "msg2", null));

        // expired() will drain buffer then fail on OpenSearch (not available) but should not throw
        logNotificationTarget.expired();