Returns an immutable map, mapping only the specified key to the specified value. The returned map is serializable.

Parameters:

<K>		the class of the map keys
<V>		the class of the map values
key		the sole key to be stored in the returned map.
value		the value to which the returned map maps key.

Returns:  an immutable map containing only the specified key-value mapping.

Since:  1.3