EL . and [] operators

[Paul Statham]

I have a query about a question in the HFSJ book

Which about EL access operators are true?

a. Anywhere the . (dot) operator is used, the [] could be used instead.
b. Anywhere the [] operator is used, the . (dot) could be used instead.
c. If the . (dot) operator is used to access a bean property but the property doesn't exist, then a runtime exception is thrown.
d. There are some situations where the . (dot) operator must be used and other situations where the [] operator must be used.

Now the answers are A + C. I chose A, C + D. It lists the reason for D not being correct as

Option D is incorrect because the dot operator can always be converted to the [] operator

Whilst it's true that the [] operator can be used for JavaBeans, Maps, Lists and Arrays. It's not true that the . (dot) operator can be used for Lists and Arrays. So there are some situations where you shouldn't use the . (dot) operator, so therefore D is a valid option. Am I right?

[Frits Walraven]

Hi Paul,

So there are some situations where you shouldn't use the . (dot) operator, so therefore D is a valid option. Am I right?

These questions are always tricky and sometimes they could be ambigious, but in your reasoning you have found:

that the [] operator must be used with a list or an array

but

you haven't found the situation that the . operator must be used because the [] operator fails to work

that is why D is not correct

Regards,
Frits

[Paul Statham]

Ah ok I see it's all in the word must! Dot is Never a must!

[bhanu chowdary]

Paul Statham wrote:Ah ok I see it's all in the word must! Dot is Never a must!

That is the catch . You can always replace a "." with []