Question regarding JSP, JSF and Struts

[noodle_variation_187-X]

Hello people,
I have read about the basics of JSP, but I haven't understood when to use pure JSP and when to use a JSP-based framework like JSF or struts. Is it possible to understand struts and JSF without being a JSP professional or is deep JSP knowledge a prerequisite to understand those frameworks?

[nicephotog]

JSF and struts require proper understanding of JSP and Java web servlets first, and also "bean writing rules".

JSP is used alike PHP or ASP , internally coded into an html page with the server recognised extension.
In essence JSP is a servlet that is integrated to the J2EE container(server).

JSF (Java Server Faces) is a "framework" for "GUI in web pages in basis" but does much more with special integration classes incorporated to the JSF framework that can talk with the server container and interact its running instance with other server frameworks in the J2ee container such as the servlets and JSP or SOA web services(WSDL services and registries), that uses the "faces servlet" configured with a special web.xml called faces-config.xml