* Collections#singletonMap(Object, Object)} and {@link java.util.LinkedHashMap} for empty,
 * singleton and regular maps respectively. For sorted maps, it's a thin wrapper around {@link
 * java.util.TreeMap}.
 *
 * @see ImmutableSortedMap
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
public abstract class ImmutableMap<K, V> implements Map<K, V>, Serializable {

        <constraint name="__context__" within="" contains="" />
      </replaceConfiguration>

import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.NoSuchElementException;
import java.util.Set;
import javax.annotation.CheckForNull;

/**
 * An implementation of {@code RangeMap} based on a {@code TreeMap}, supporting all optional
 * operations.
 *
 * <p>Like all {@code RangeMap} implementations, this supports neither null keys nor null values.
 *
 * @author Louis Wasserman
 * @since 14.0
 */

      Iterator<Map<C, V>> iterator = backingMap.values().iterator();
      while (iterator.hasNext()) {
        Map<C, V> map = iterator.next();
        // map.keySet().removeAll(c) can throw a NPE when map is a TreeMap with
        // natural ordering and c contains a null.
        if (Iterators.removeAll(map.keySet().iterator(), c)) {
          changed = true;
          if (map.isEmpty()) {
            iterator.remove();

 * for that key. The subclass should not call {@link #createCollection()} directly, and a new
 * instance should be created every time the method is called.
 *
 * <p>For example, the subclass could pass a {@link java.util.TreeMap} during construction, and
 * {@link #createCollection()} could return a {@link java.util.TreeSet}, in which case the
 * multimap's iterators would propagate through the keys and values in sorted order.
 *

 * for that key. The subclass should not call {@link #createCollection()} directly, and a new
 * instance should be created every time the method is called.
 *
 * <p>For example, the subclass could pass a {@link java.util.TreeMap} during construction, and
 * {@link #createCollection()} could return a {@link java.util.TreeSet}, in which case the
 * multimap's iterators would propagate through the keys and values in sorted order.
 *