Returns an unmodifiable view of the specified navigable map. Query operations on the returned navigable map "read through" to the specified navigable map. Attempts to modify the returned navigable map, whether direct, via its collection views, or via its subMap, headMap, or tailMap views, result in an UnsupportedOperationException.

The returned navigable map will be serializable if the specified navigable map is serializable.

Parameters:

<K>		the class of the map keys
<V>		the class of the map values
m		the navigable map for which an unmodifiable view is to be returned

Returns:  an unmodifiable view of the specified navigable map

Since:  1.8