235 
 236     /**
 237      * Constructs a new, empty {@code WeakHashMap} with the default initial
 238      * capacity (16) and load factor (0.75).
 239      */
 240     public WeakHashMap() {
 241         this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR);
 242     }
 243 
 244     /**
 245      * Constructs a new {@code WeakHashMap} with the same mappings as the
 246      * specified map.  The {@code WeakHashMap} is created with the default
 247      * load factor (0.75) and an initial capacity sufficient to hold the
 248      * mappings in the specified map.
 249      *
 250      * @param   m the map whose mappings are to be placed in this map
 251      * @throws  NullPointerException if the specified map is null
 252      * @since   1.3
 253      */
 254     public WeakHashMap(Map<? extends K, ? extends V> m) {
 255         this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
 256                 DEFAULT_INITIAL_CAPACITY),
 257              DEFAULT_LOAD_FACTOR);
 258         putAll(m);
 259     }
 260 
 261     // internal utilities
 262 
 263     /**
 264      * Value representing null keys inside tables.
 265      */
 266     private static final Object NULL_KEY = new Object();
 267 
 268     /**
 269      * Use NULL_KEY for key if it is null.
 270      */
 271     private static Object maskNull(Object key) {
 272         return (key == null) ? NULL_KEY : key;
 273     }
 274 
 275     /**

 235 
 236     /**
 237      * Constructs a new, empty {@code WeakHashMap} with the default initial
 238      * capacity (16) and load factor (0.75).
 239      */
 240     public WeakHashMap() {
 241         this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR);
 242     }
 243 
 244     /**
 245      * Constructs a new {@code WeakHashMap} with the same mappings as the
 246      * specified map.  The {@code WeakHashMap} is created with the default
 247      * load factor (0.75) and an initial capacity sufficient to hold the
 248      * mappings in the specified map.
 249      *
 250      * @param   m the map whose mappings are to be placed in this map
 251      * @throws  NullPointerException if the specified map is null
 252      * @since   1.3
 253      */
 254     public WeakHashMap(Map<? extends K, ? extends V> m) {
 255         this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR + 1),
 256                 DEFAULT_INITIAL_CAPACITY),
 257              DEFAULT_LOAD_FACTOR);
 258         putAll(m);
 259     }
 260 
 261     // internal utilities
 262 
 263     /**
 264      * Value representing null keys inside tables.
 265      */
 266     private static final Object NULL_KEY = new Object();
 267 
 268     /**
 269      * Use NULL_KEY for key if it is null.
 270      */
 271     private static Object maskNull(Object key) {
 272         return (key == null) ? NULL_KEY : key;
 273     }
 274 
 275     /**