SynchronizedMap(Map m) 
{
        // Object on which to synchronize
            if (m==null)
                throw new NullPointerException();
            this.m = m;
            mutex = this;
}

 SynchronizedMap(Map m,
    Object mutex) 
{
            this.m = m;
            this.mutex = mutex;
}

 public  void clear() 
{
            synchronized(mutex) {m.clear();}
}

 public boolean containsKey(Object key) 
{
            synchronized(mutex) {return m.containsKey(key);}
}

 public boolean containsValue(Object value) 
{
            synchronized(mutex) {return m.containsValue(value);}
}

 public Set entrySet() 
{
            synchronized(mutex) {
                if (entrySet==null)
                    entrySet = new SynchronizedSet< Map.Entry< K,V > >(m.entrySet(), mutex);
                return entrySet;
            }
}

 public boolean equals(Object o) 
{
            synchronized(mutex) {return m.equals(o);}
}

 public V get(Object key) 
{
            synchronized(mutex) {return m.get(key);}
}

 public int hashCode() 
{
            synchronized(mutex) {return m.hashCode();}
}

 public boolean isEmpty() 
{
            synchronized(mutex) {return m.isEmpty();}
}

 public Set keySet() 
{
           
            synchronized(mutex) {
                if (keySet==null)
                    keySet = new SynchronizedSet< K >(m.keySet(), mutex);
                return keySet;
            }
}

 public V put(K key,
    V value) 
{
            synchronized(mutex) {return m.put(key, value);}
}

 public  void putAll(Map map) 
{
            synchronized(mutex) {m.putAll(map);}
}

 public V remove(Object key) 
{
            synchronized(mutex) {return m.remove(key);}
}

 public int size() 
{
            synchronized(mutex) {return m.size();}
}

 public String toString() 
{
            synchronized(mutex) {return m.toString();}
}

 public Collection values() 
{
            synchronized(mutex) {
                if (values==null)
                    values = new SynchronizedCollection< V >(m.values(), mutex);
                return values;
            }
}