@Override
    public V remove(final Object key)
	throws ConcurrentModificationException {

        checkKey(key);

        return (V)doRemove(key, KEY);
    }
@Override
    public V remove(final Object key)
	throws ConcurrentModificationException {

        checkKey(key);

        return (V)doRemove(key, KEY);
    }
@ Override public V remove ( final Object key ) throws ConcurrentModificationException { checkKey ( key ) ; return ( V ) doRemove ( key , KEY ) ; }
Removes the mapping for this key from this map if present

@param key key whose mapping is to be removed from the map.

@return previous value associated with specified key, or null
if there was no mapping for key.
Removes the mapping for this key from this map if present