hi me tooi am learning jsp but i am haviong big porblem simply because i havent done java before.

Get a GOOD book. "Head First Servlets and JSP" is a good place to start, followed by "Java Server Pages, 3rd edition" (do NOT go for an previous edition or you get outdated knowledge) .

http://www.oreilly.com/catalog/headservletsjsp/
http://www.oreilly.com/catalog/jserverpages3/

The web frontend for any serverside application written in Java.

Then you should start learning Java first, unless you don't plan on doing anything but web frontends for things other people write.
You don't NEED to know Java to write modern JSP, as you should NEVER have to use scriptlet code. And if you never need to write the servlets and other classes delivering the data to the JSPs, you will never see a line of Java code if you do the job properly.

Well thanks for the reply

but i already know Java and Servlets and i just asked structure in which i should learn JSP

i think you didnt got my question

I am aksing how shall i proceed with my learning

like first i should do Custome tags or Scriptlets or something else

NEVER use scriptlets.
Custom tags are hardly ever needed (pretty much reserved for framework developers now that JSTL and JSF are here), at least when it comes to creating them.

Concentrate on learning proper application design (and the books should help with that).

You might also study Spring, which helps a lot towards getting a proper design in place.
Wicket is also getting a decent following.

Bypass Struts, it's old and tired and by now recognised to be not all that good.