Few Doubts in HFSJ book

[georgy jacob]

Hi,

I am planning to take the exam on the 13 th of March. I have a few doubts.Could u please get them clarified ?

1) Its mentioned in HFSJ that EL handles null values gracefully and doesnt print null if a null value is passed.
But on pg :509

<mytags:simple>
message is ${message}
</mytags:simple>
its said that if${message occurs out of the scope of the tag null will be printed .
Isnt it supposed to not print anything rather than null


2) while we are implementing the tag handler class are we supposed to write a no arg constructor in the tag handler in case we have a constructor which takes in one argument
for ex :
class Test extends SimpleTag Support
{
Test(int a)
{ }
// attribute setters and getters defined here

}
Now will the above code compile if i dont write a no arg constructor ?


3) response.encodeRedirectURL()does redirecting to a URL inaddition to encoding the url . Am i right here ? But in the mock exam there is a qn which asks which of the following methods can redirect to a different URL (one option given is response.encoderedirectURL) but response.encodeRedirectURl is not given as a correct option there.Could u please clarify on this issue as wel

Thanking u in advance,
Georgy

[Narendra Dhande]

Hi

1) Pl. specify the full description about this. The message is attribute or variable.

2) while we are implementing the tag handler class are we supposed to write a no arg constructor in the tag handler in case we have a constructor which takes in one argument
for ex :
class Test extends SimpleTag Support
{
Test(int a)
{ }
// attribute setters and getters defined here

}
Now will the above code compile if i dont write a no arg constructor ?

I think there is no compilation error the file will compile successfully. The compile-time error occurs when you use the Tag in the JSP file. Because at the time of compilation of JSP file the container validate all the tag libraries. The containe will not find the default construcutor for the tag handler and give compile time error.

Thanks

3) response.encodeRedirectURL()does redirecting to a URL inaddition to encoding the url . Am i right here ? But in the mock exam there is a qn which asks which of the following methods can redirect to a different URL (one option given is response.encoderedirectURL) but response.encodeRedirectURl is not given as a correct option there.Could u please clarify on this issue as wel

The response.encodeRedirectURL does not do the redirecting job. It only encode the URL. You still require to use the sendRedirect.

[georgy jacob]

Thank you so much Narendra . My doubt has been cleared

For the first querry message is an attribute which is set in the tag handler

[Narendra Dhande]

Hi,

Assuming that the "message" attribute is placed in page scope, this attribute is visible onlt in the tag. that in <prefix.tag> .... </prefix.tag> including body.

Thanks