*     {@code RuntimeException} as its cause
   * @throws ExecutionError if {@code get} throws an {@code ExecutionException} with an {@code
   *     Error} as its cause
   * @throws CancellationException if {@code get} throws a {@code CancellationException}
   * @throws IllegalArgumentException if {@code exceptionClass} extends {@code RuntimeException} or
   *     does not have a suitable constructor
   * @since 19.0 (in 10.0 as {@code get})

    ClosingFuture<String> step4 =
        step3.catching(
            CancellationException.class,
            step4Waiter.waitFor(
                new ClosingFunction<CancellationException, String>() {
                  @Override
                  public String apply(DeferredCloser closer, CancellationException input)
                      throws Exception {

import java.util.AbstractSet;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReferenceArray;
import java.util.concurrent.locks.ReentrantLock;