JSP - Why does this work?

I created a simple JSP with just a couple of out.println statements within sciplet tags. It worked perfectly, no errors.
Question: I never defined object "out", is "out" something that get built into every JSP for free?? Are there other objects that do not need to be created?
I am using JavaWebServer2.0
Thanks.

First of the the creation of out or any other IMPLICIT OBJECTS is not dependent on web server (jsp engine).
There are quite a few implicit objects you get for free when you create a jsp.
1. JspWriter out;
2. PageContext pageContext;
3. Httpsession session;
4. HttpServletRequest request;
5. HttpServletResponse response;
6. ServletContext application;
7. ServletConfig config;
8. Object page;

Thanks!