Java: Stacked (layered) maps behind a Map interface?

You can have Stack as a wrapper. Have a Map<'String, Map> ( String here is for the name of the map). Expose push and pop as API. Interesting part of your question is, defining push and pop? How would the signature of these method actually look like? Actually, not very clear is to what you are trying to achieve?

So, there is no such builtin structure in the JDK, but it can be implemented using a LinkedList containing Maps.

LinkedList implements all three of List, Queue and Deque, maybe it's a little overkill, but ohwell...

A sample code would be as follows; however, the Map interface is not really obeyed (curious how you'd do .equals() and .hashCode() here? Not even talking about .clear()):

public final class StackedMap<K, V>
    implements Map<K, V>
{
    private final Map<K, V> NO_MAP = new HashMap<K, V>();
    private final LinkedList<Map<K, V>> maps = new LinkedList<>();

    private Map<K, V> currentMap = NO_MAP;

    public void push(Map<K, V> map)
    {
        maps.push(map);
        currentMap = map;
    }

    public Map<K, V> pop()
    {
        return currentMap = maps.pop();
    }

    @Override
    public V get(K key)
    {
        V ret;

        for (final Map<K, V> map: maps)
            if ((ret = map.get(key)) != null)
                break;
        return ret;
    }

    // etc
}

Untested etc.