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 inside another HashMap i.e. a nested HashMap, how would i access the contents? Can i do this like this, inline:

HashMap.get("keyname").get("nestedkeyname"); 

Thank you.

Answer 1

You can do it like you assumed. But your HashMap has to be templated:

Map<String, Map<String, String>> map =      new HashMap<String, Map<String, String>>(); 

Otherwise you have to do a cast to Map after you retrieve the second map from the first.

Map map = new HashMap(); ((Map)map.get( "keyname" )).get( "nestedkeyname" );