I'm not a total beginner in Java, but I just don't know the skills I need to make a jump to JSP. I have been programming with PHP for a few months now.
It depends on what you are doing with JSP. To do any of the business logic will require you to know java.
It would be like knowing just how to use echo
in PHP and doing the html/css/javascript. You can get some done, but that means that someone else will have done the work of creating the rest of the php code to go to the database or any other resource.
If you are going to just be a UI designer then you may want to look at some of the frameworks, such as JavaServer Faces, and see if that will help you.
Ultimately, to do anything useful you will need to learn Java though, how much, and what parts depends on what it is you are doing.
If you wanted to use JSP as if it were old-school PHP, you'd be up to speed after a day or two.
If you want to buy into something "enterpise"-like JBoss, etc, you'll need a long time. (I think I just threw up in my mouth...)
What's your motivation from "jumping to" JSP. (I'm not sure it's a jump in the right direction...).
Just start with a small fun project and see where you hitting walls. Then try to figure out how to resolve the problems. For your second project you will know how to start to avoid these problems.
I would recommend to get a good reference book that introduces you to the whole java web programming culture, if you really want to get started with that.
You should be able to convert the UML and the constructs used there into something you can use with PHP and maybe thats the way to ge before you start to use another big big monster.