About Question enthuware.jwpv6.2.1020 :

[ETS User]

Why is this correct ?

${map[map["2"]]}

Isn't this a map of a map ?

[Guest]

map["2"] returns "3" and this result is used as argument for the second map call. And this will return 4.

[chibee1620]

When do you have to put quotes around the contents of [] in el?
whats the difference between ${map[map[2]]} and ${map[map["2"]]}?

[Vimal]

Yeah..
whats the difference between ${map[map[2]]} and ${map[map["2"]]}?

Anybody to help>..

[admin]

Please go through Section 1.6 of Expression Language Specification 2.2, which explains this very clearly.

The EL follows ECMAScript in unifying the treatment of the . and [] operators.
expr-a.identifier-b is equivalent to expr-a["identifier-b"]; that is, the
identifier identifier-b is used to construct a literal whose value is the identifier,
and then the [] operator is used with that value.
Similarly, expr-a.identifier-b(params)is equivalent to expra["
identifier-b"](params).

[dhanuddhara]

Could someone explain me, why option 3 is wrong?
when considering question on 'enthuware.jwpv6.2.1019' it also should be a correct answer.

[admin]

3 is not a valid identifier. It is an integer and is interpreted as an index. That is why map.o is ok (as is the case in 2.1019) but map.3 is not.

HTH,
Paul.

[shareef.hiasat]

Please go through Section 1.6 of Expression Language Specification 2.2, which explains this very clearly.

The EL follows ECMAScript in unifying the treatment of the . and [] operators.
expr-a.identifier-b is equivalent to expr-a["identifier-b"]; that is, the
identifier identifier-b is used to construct a literal whose value is the identifier,
and then the [] operator is used with that value.
Similarly, expr-a.identifier-b(params)is equivalent to expra["
identifier-b"](params).

sorry but am not convinced can you put it in simpler words thanks
any reference example on internet would be good thanks

and why the question has no explanation ! it is categorized as tought right!

[admin]

Sure, can you tell me with which part exactly do you have trouble understanding?
For examples, you can try writing short jsp programs and run it under tomcat.
-Paul.