* 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 {

  abstract static class IteratorBasedImmutableMap<K, V> extends ImmutableMap<K, V> {

     * Returns a newly-created immutable map, using the last value for any key that was added more
     * than once. The iteration order of the returned map is the order in which entries were
     * inserted into the builder, unless {@link #orderEntriesByValue} was called, in which case
     * entries are sorted by value. If a key was added more than once, it appears in iteration order

     * Returns a newly-created immutable map, using the last value for any key that was added more
     * than once. The iteration order of the returned map is the order in which entries were
     * inserted into the builder, unless {@link #orderEntriesByValue} was called, in which case
     * entries are sorted by value. If a key was added more than once, it appears in iteration order