How do I access nested HashMaps in Java?

Question

I have a HashMap in Java, the contents of which (as you all probably know) can be accessed by

HashMap.get(\"keyname\");

If a have a HashMap

Answer 1

Yes, if you use the proper generic type signature for the outer hashmap.

HashMap> hm = new HashMap>();
// populate the map
hm.get("keyname").get("nestedkeyname");

If you're not using generics, you'd have to do a cast to convert the object retrieved from the outer hash map to a HashMap (or at least a Map) before you could call its get() method. But you should be using generics ;-)