* The easiest way to pin a host is turn on pinning with a broken configuration and read the
 * expected configuration when the connection fails. Be sure to do this on a trusted network, and
 * without man-in-the-middle tools like [Charles][charles] or [Fiddler][fiddler].
 *
 * For example, to pin `https://publicobject.com`, start with a broken configuration:
 *
 * ```java
 * String hostname = "publicobject.com";

 * in terms of {@link #invalidate}. The method {@link #cleanUp} is a no-op. All other methods throw
 * an {@link UnsupportedOperationException}.
 *
 * @author Charles Fry
 * @since 11.0
 */
@GwtIncompatible
public abstract class AbstractLoadingCache<K, V> extends AbstractCache<K, V>
    implements LoadingCache<K, V> {

  /** Constructor for use by subclasses. */

 *
 * <p>Note that {@link #get}, {@link #getUnchecked}, and {@link #apply} all expose the same
 * underlying functionality, so should probably be overridden as a group.
 *
 * @author Charles Fry
 * @since 11.0
 */
@GwtIncompatible
public abstract class ForwardingLoadingCache<K, V> extends ForwardingCache<K, V>
    implements LoadingCache<K, V> {

  /** Constructor for use by subclasses. */

 * in terms of {@link #invalidate}. The method {@link #cleanUp} is a no-op. All other methods throw
 * an {@link UnsupportedOperationException}.
 *
 * @author Charles Fry
 * @since 11.0
 */
@GwtIncompatible
public abstract class AbstractLoadingCache<K, V> extends AbstractCache<K, V>
    implements LoadingCache<K, V> {

  /** Constructor for use by subclasses. */

 *
 * <p>Note that {@link #get}, {@link #getUnchecked}, and {@link #apply} all expose the same
 * underlying functionality, so should probably be overridden as a group.
 *
 * @author Charles Fry
 * @since 11.0
 */
@GwtIncompatible
public abstract class ForwardingLoadingCache<K, V> extends ForwardingCache<K, V>
    implements LoadingCache<K, V> {

  /** Constructor for use by subclasses. */

 * more methods to modify the behavior of the backing cache as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * @author Charles Fry
 * @since 10.0
 */
@GwtIncompatible
public abstract class ForwardingCache<K, V> extends ForwardingObject implements Cache<K, V> {

  /** Constructor for use by subclasses. */
  protected ForwardingCache() {}

 * more methods to modify the behavior of the backing cache as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * @author Charles Fry
 * @since 10.0
 */
@GwtIncompatible
public abstract class ForwardingCache<K, V> extends ForwardingObject implements Cache<K, V> {

  /** Constructor for use by subclasses. */
  protected ForwardingCache() {}

 * by multiple concurrent threads.
 *
 * @param <K> the type of the cache's keys, which are not permitted to be null
 * @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> {

  /**

 * #getUnchecked}.
 *
 * @param <K> the type of the cache's keys, which are not permitted to be null
 * @param <V> the type of the cache's values, which are not permitted to be null
 * @author Charles Fry
 * @since 11.0
 */
@GwtCompatible
public interface LoadingCache<K, V> extends Cache<K, V>, Function<K, V> {

  /**
   * Returns the value associated with {@code key} in this cache, first loading that value if

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicReference;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * @author Charles Fry
 */
@NullUnmarked
public class LocalLoadingCacheTest extends TestCase {

  private static <K, V> LocalLoadingCache<K, V> makeCache(
      CacheBuilder<K, V> builder, CacheLoader<? super K, V> loader) {