Can we place the any object to key attribute of HashMap<key,value>?

Can we place the any object to key attribute of
HashMap<key,value>?

Question Posted / ramaraok

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Can we place the any object to key attribute of HashMap<key,value>?..

Answer / abhijeet

Hi,
I am giving you a collective answer. Yes you can use any
object as key in hashmap. But if you r sure that u will be
using diferent objects as key then u dont ve to overide
anything. But if you are going to use same object as key
then you need to override hashcode and equals method. Be
sure that your equals method returns false if you need to
use the object as key.

But this is tricky 1 and in live enviroment its not needed :-)
only for interview to impress interviewwer :-)

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8 Yes

1 No

Can we place the any object to key attribute of HashMap<key,value>?..

Answer / ramarao katta

yes, we can place any object as key value but that object
must and should implement the hashcode method.

Is This Answer Correct ?

5 Yes

2 No

Can we place the any object to key attribute of HashMap<key,value>?..

Answer / patil abhijeet

Hi Ramarao,
Its not necessary to override hashCode() since hashcode is
default generated for every object. Please try my example n
check it by urself

Is This Answer Correct ?

4 Yes

2 No

Can we place the any object to key attribute of HashMap<key,value>?..

Answer / patil abhijeet

Yes we can use object as the key

person p = new person();

HashMap m = new HashMap()
m.put(p,"mysqlf");
above works perfectly fy9 ..... but dont try to use the same
object as key twice :-)

Is This Answer Correct ?

5 Yes

6 No

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