* throwing an exception, if passed a {@code toKey} greater than an earlier {@code toKey}.
   */
  @Override
  public ImmutableSortedMap<K, V> subMap(K fromKey, K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  /**
   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys ranges

   * @throws IllegalArgumentException if {@code size} is negative
   */
  @CanIgnoreReturnValue
  public static int checkElementIndex(int index, int size) {
    return checkElementIndex(index, size, "index");
  }

  /**
   * Ensures that {@code index} specifies a valid <i>element</i> in an array, list or string of size

  /**
   * Test-helper method that performs {@code nThreads} concurrent calls to {@code cache.get(key)} or
   * {@code cache.getUnchecked(key)}, and returns a List containing each of the results. The result
   * for any given call to {@code cache.get} or {@code cache.getUnchecked} is the value returned, or
   * the exception thrown.
   *
   * <p>As we iterate from {@code 0} to {@code nThreads}, threads with an even index will call

  }

  @GwtIncompatible // Only used by @GwtIncompatible code
  private abstract static class EmptyIteratorTester extends IteratorTester<Integer> {
    protected EmptyIteratorTester() {
      super(3, MODIFIABLE, Collections.<Integer>emptySet(), IteratorTester.KnownOrder.KNOWN_ORDER);
    }
  }

  @GwtIncompatible // Only used by @GwtIncompatible code

    new EqualsTester().addEqualityGroup(forward, reverse).testEquals();
  }

  /**
   * Test that a hash code miscomputed by "input.hashCode() * tooFarValue / 2" is correct under our
   * {@code hashCode} implementation.
   */
  public void testPowerSetHashCode_inputHashCodeTimesTooFarValueIsZero() {
    Set<Object> sumToEighthMaxIntElements =

  }

  /**
   * Sets the result of this {@code Future} unless this {@code Future} has already been cancelled or
   * set (including {@linkplain #setFuture set asynchronously}). When a call to this method returns,
   * the {@code Future} is guaranteed to be {@linkplain #isDone done} <b>only if</b> the call was
   * accepted (in which case it returns {@code true}). If it returns {@code false}, the {@code

   * throwing an exception, if passed a {@code toKey} greater than an earlier {@code toKey}.
   */
  @Override
  public ImmutableSortedMap<K, V> subMap(K fromKey, K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  /**
   * This method returns a {@code ImmutableSortedMap}, consisting of the entries whose keys ranges

  /**
   * Test-helper method that performs {@code nThreads} concurrent calls to {@code cache.get(key)} or
   * {@code cache.getUnchecked(key)}, and returns a List containing each of the results. The result
   * for any given call to {@code cache.get} or {@code cache.getUnchecked} is the value returned, or
   * the exception thrown.
   *
   * <p>As we iterate from {@code 0} to {@code nThreads}, threads with an even index will call

/**
 * Synchronized collection views. The returned synchronized collection views are serializable if the
 * backing collection and the mutex are serializable.
 *
 * <p>If {@code null} is passed as the {@code mutex} parameter to any of this class's top-level
 * methods or inner class constructors, the created object uses itself as the synchronization mutex.
 *
 * <p>This class should be used by other collection classes only.

import java.util.SortedSet;
import java.util.TreeMap;
import java.util.concurrent.ConcurrentMap;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Unit test for {@code Maps}.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class MapsTest extends TestCase {