Hashtable allowing null values

[Ra Sank]

Hi,

I have tried the below code and it is allowing both null as key as well as values. based on difference between HashMap and Hashtable several tutorials mentioning null is not allowable in Hashtable afterwards of Synchronized difference. Kindly clarify if you have any idea on this.

  Hashtable<String,String> ht = new Hashtable<String,String>();
ht.put("null","null");
ht.put("","");
    

If these statements are correct then is there any other difference between HashMap and Hashtable?

[Wirianto Djunaidi]

because you are passing a string that contains the value "null" instead passing null keyword that represent nothing.

[Ra Sank]

Hi Wirianto,

Thanks for your updates.

Can you please tell me whether i can do like this for the check

ht.put(null,null); Which doesnt affect the Hashtable?.

[Rob Spoor]

That code will throw a NullPointerException with Hashtable.