@Override
              protected SortedMap<String, String> create(Entry<String, String>[] entries) {
                return populate(new ConcurrentSkipListMap<String, String>(), entries);
              }
            })
        .named("ConcurrentSkipListMap, natural")
        .withFeatures(
            MapFeature.GENERAL_PURPOSE,
            CollectionFeature.SUPPORTS_ITERATOR_REMOVE,

              @Override
              protected SortedMap<String, String> create(Entry<String, String>[] entries) {
                return populate(new ConcurrentSkipListMap<String, String>(), entries);
              }
            })
        .named("ConcurrentSkipListMap, natural")
        .withFeatures(
            MapFeature.GENERAL_PURPOSE,
            CollectionFeature.SUPPORTS_ITERATOR_REMOVE,

import java.util.List;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;

import java.util.Random;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListMap;

/**
 * Helper classes for various benchmarks.
 *
 * @author Christopher Swenson
 */
final class BenchmarkHelpers {

import java.util.Random;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListMap;

/**
 * Helper classes for various benchmarks.
 *
 * @author Christopher Swenson
 */
final class BenchmarkHelpers {