How to declare HashMap in HashMap

[Sujith Mahesh]

Hi,

I want to declare a HashMap where key is of the type "String" and value is a "HashMap".
Here is what I want to declare,

  
HashMap<String, HashMap<String, HashMap<--and so on>>> aMap = 
new HashMap<String, HashMap<String, HashMap<--and so on>>>;

How do I declare this in Java 5.0?

[David O'Meara]

"Sujith",
Please check your private messages.
-DOM

[ramya narayanan]

I think so it will work

HashMap hm1=new HashMap();
HashMap hm2=new HashMap();
hm2.put("key",hm1);

There is term "map of maps " which describe this functionality.
Regards

[rakesh sugirtharaj]

Just the way you have written it. What exactly is your doubt here?

[Campbell Ritchie]

Better to declare the Map as type Map<String, Map<Foo>>.

[Rob Spoor]

The problem in this case can be the length of the overall declaration:

Map<String, Map<String, Map<String, Map<String, Map<String, Object>>>>>

There's not a lot you can do about that though. Either you will have to deal with the length, or lower the constraint in the declaration and cast instead.

[Sujith Mahesh]

Thanks Rob,

I will declare like this

 Map<String, Map<String, Object >>   

and While accessing the object I will cast it.