Here are some mock exams found on the internet.

The Poddar Questions - exam questions and answers edited by Amit Poddar (25/12/1999).
The Boone Exam. It consists of 70 questions of question similar to the exam (03/15/1998).
Sun's examples. It consists of 6 questions which are definitely in the exam of several JDK's. (25/12/1999).
The Majji Papers. It consists of 30 questions edited by Sreenivasa Kumar Majji (23/01/2000)
Marcus Green's 60 exam questions (24/03/1999)
The Sarga questions (28/08/2000).
Green's Exam Cram 60 questions (27/01/2001)
http://javaranch.com/mock.jsp

JDCert, free exam simulator written in Java (11/01/2000).
Jargon - Jargon is a free simulation tool for SCJP examination and has 140 questions. (23/01/2000)
gEs - Java based SCJP Exam Simulator with over 250 questions developed by Sun Certified Java Programmers. 15 questions for free (21-11-1999)
http://www.axtive.com/jcertify - a self study tool (not free!), looks oke! (24-08-1999)
Jxam 1.81, free exam simulator written in Java, about 170 questions (24/01/2000)

http://certify.torolab.ibm.com/ - IBM certification tool with 30 questions, login and go (25/12/1999)
LanWright - This applet simulates the environment of the Java 2 Programmer Certification Exam as administered by Sylvan Prometric (04/04/1999)
LanWright - This collection of 19 of the hardest questions of the Java 2 Programmer Certification Exam (22/10/1999)
http://www.software.u-net.com/applets/Exam/Exam.htm - another exam simulation (04-04-1999)
http://bmil.freeservers.com/tester/test.html - Exam simulation applet with 64 questions (25-12-1999)
MindQ offers an online test after filling in a form (29/03/1999).
Java Certification Objectives List. It consists of sylabus description that nearly matches all the questions in the exam. (2/11/1999)
Java 1.1 - Sun Certified Programmer Examination Revision Book (22/10/1999)
Exam notes http://www.geocities.com/SiliconValley/Circuit/8217/  (24/03/1999)
The Desboro Objectives - Very condensed and beautiful written study help (24/01/1999)
The LevTeck connection - Miscellanious study material and links (28/08/2000).
http://home2.swipnet.se/~w-20121/javastore/cert/index.html (25/03/1999)

http://javacert.com - a site dedicated to certification and discussing the certification.
http://www.javaranch.com/mock.html - a site with references to mockups, test etc (23/01/2000)

Java_Cert_Forum

http://discussions.earthweb.com/cgi-bin/dnewsweb?cmd=xover&group=earthweb.gocertify.java&utag=

mock_exams

http://www.jaworski.com/java/certification/

http://www.michael-thomas.com/

http://www.geocities.com/SiliconValley/Network/3693/othersites.html

http://abhinavgupta.tripod.com/JavaCert/downloads.html

http://home-1.worldonline.nl/~bmc88/java/javacert/

http://www.geocities.com/SiliconValley/Screen/5046/ftest1.html

http://www.anilbachi.8m.com/

http://members.dencity.com/jitendra/javaworld/JTest.html

http://jquest.webjump.com/

http://www.levteck.com/

http://www.jchq.net/

http://joppa.appliedreasoning.com/JavaCertification.html

http://jahanns.virtualave.net/freemock.html

http://www.lanw.com/java/javacert/HardestTest.htm

http://www.geocities.com/SiliconValley/Cable/1025/exam1.html

http://www.javaranch.com/mock.jsp

http://www.javaranch.com/maha/_Mock_Exams/JohnJuntMockExam.htm

JavaCert

http://apollo.netservers.com/~femibyte/javaquestions.html

http://javacert.com/

http://www.lanw.com/java/javacert/default.htm

http://www.javaprepare.com/

http://www.ii.uib.no/~khalid/pgjc/jcbook/engine.html

http://www.acmerocket.com/skinny/

JAVA Study

http://www.swtech.com/java/cert/

http://www.javaprepare.com/faq.html

http://www.artima.com/jini/jf/intro/messages/137.html

http://www.javamug.org/Certification.html

http://certify.torolab.ibm.com/login.jsp

http://members.theglobe.com/apoddar/questions.html

http://www.absolutejava.com/articles/test-your-java-knowledge.html

http://www.ddj.com/articles/2000/0010/0010m/0010m.htm

http://jahanns.virtualave.net/freemock.html

http://www.vivek.4mg.com/

http://www.dougsparling.com/comp/links/javacert/index.html

http://myhome.netsgo.com/ymab3408/java/scjp01.htm

http://myhome.netsgo.com/ymab3408/java/scjp03.htm

http://www.javacommerce.com/certify/exams.html

http://nav.webring.yahoo.com/hub?ring=javacert&list

http://www.geocities.com/chitrasridhar/noframes/certify.html

http://valiveru.tripod.com/java/jvaltest.html

http://www.javamug.org/Certification.html

http://www1.domaindlx.com/shahzadgodil/SJCP_Links/body_sjcp_links.html

http://tco2.tco.net/Directory/Computers/Programming/Languages/Java/Resource_Sites/Java_Certification/

http://www.jaworski.com/java/certification/

http://abhinavgupta.tripod.com/JavaCert/

Software design pattern

http://www.ciol.com/content/technology/sw_desg_patt/toc.asp

• Design Pattern Home Page: http://hillside.net/patterns/
• Schmidt's Design Patterns, Pattern Languages, and Frameworks: http://www.cs.wustl.edu/~schmidt/patterns.html
• Patterns and Java examples: http://www.ciol.com/content/technology/sw_desg_patt/toc.asp
• Patterns and Java examples: http://www.research.umbc.edu/~tarr/cs491/fall00/cs491.html

JDBC metadata:
http://members.aol.com/kgb1001001/Articles/JDBCMetadata/JDBC_Metadata.htm
http://www.javaworld.com/javaworld/javatips/jw-javatip82.html
http://www.devx.com/upload/free/features/javapro/1999/06jun99/bs0699/bs0699.asp
Object-relational mapping:
http://www.object-relational.com/articles/object-relational_mapping.html
Java reflections API:
http://www.cocoon.com/writings/reflection.html
http://java.sun.com/docs/books/tutorial/reflect/TOC.html
XMI:
http://www-3.ibm.com/software/ad/library/standards/xmi.html