* that is not contained in {@code set1}.
   *
   * <p>Results are undefined if {@code set1} and {@code set2} are sets based on different
   * equivalence relations, for example if {@code set1} is a {@link HashSet} and {@code set2} is a
   * {@link TreeSet} or the {@link Map#keySet} of an {@code IdentityHashMap}.
   */
  public static <E extends @Nullable Object> SetView<E> union(

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReferenceArray;
import java.util.logging.LogRecord;
import junit.framework.TestCase;

/**
 * Tests relating to cache loading: concurrent loading, exceptions during loading, etc.
 *
 * @author mike nonemacher
 */
public class CacheLoadingTest extends TestCase {
  TestLogHandler logHandler;

  @Override