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HashMap

Ida Achi
Greenhorn

Joined: Oct 02, 2009
Posts: 25

Please explain me the following statement maybe with a code example:

HashMap allows one null key and multiple null values in a collection.


Thank you.
Rajeev Rnair
Ranch Hand

Joined: Mar 22, 2010
Posts: 308

Ida Achi wrote:
Please explain me the following statement maybe with a code example:

HashMap allows one null key and multiple null values in a collection.


Thank you.




the above code prints ..
{null=null, 1=null, 2=null, 3=null, 4=null}
Hope this is clear!!!


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Ida Achi
Greenhorn

Joined: Oct 02, 2009
Posts: 25

Thanks mate. I just get overly confused at times.
Jesper de Jong
Java Cowboy
Saloon Keeper

Joined: Aug 16, 2005
Posts: 14193
    
  20

The point to remember is that keys in a HashMap must be unique - because of this, there can ofcourse be only one entry in the map which has null as the key.

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