I plan to write the SCWCD exam. I don't have any experience in J2EE. Thus I am little hesitant and apprehensive. I got "Head first" however few topics of servlets just went above my head. God knows what'll happen when I reach the JSP topics.
What is more important --theory or the implementation(practicals)? Any advice as to how many hours I should devote?
Both is necessary in equal measures eventhough i would personally favour on the side of practising examples given in the book. Download tomcat and install it. Get servlet spec 2.4 and jsp spec 2.0 and jstl spec 1.0.Read HFSJ every day for atleast an hour and then when you get some doubt first try implementing and cross checking book examples using the tomcat container and then still if you have problems post your query here.