There are a number of books available for this exam. I am giving you there details
1) Head First JSP and Servlets
2) SCWCD Exam Study kit by HanumantDeshmukh,Jignesh Malavia (Manning Publications)
3) Professional SCWCD Certification by Daniel Jepp,Sam Dalton(Wrox publication)
The most popular is the Ist one (Head First JSP and Servlets). Even I am using it for SCWCD preparation.
Thanks & Regards