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Sun Java Certification
by
Wyndham Ackroyd
Overview
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Part I
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Part II
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Sun Certified Java Programmer Objectives and
resources
Part III
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What is certification, FAQ’s and types of
certification
Sample Questions
Summary
Questions
Part I
What is certification,
FAQ’s and
types of certification
Where do I start?
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Do I want to be certified (am I mad enough to be
certified)?
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What is java certification?
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Certification is tough but rewarding. You will be more
confident and capable using Java after certification
It is an industry recognised certification
A way of proving that you understand java and can use java
technology
Recognised by employers and peers alike
How do I get certified?
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You have to choose a certification option
Study the material
Book, sit and pass the corresponding exam
How do I get certified?
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Choose a certification option (exam)
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Study the material
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There are 8 certification options
Create a plan of attack
Buy books and/or courses
Drag-net the web
Meet up with like minded people and set targets and goals
Book, sit and pass the corresponding exam
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Buy an exam voucher
Book the exam online from the Sun site. A third party
actually hosts the exam (called a Prometric Testing Centre)
not Sun
Turn up for a couple of hours and answer the minimum
number of multi choice questions in the allotted time
Java Certification Roadmap
Shamelessly plagiarised directly from http://www.sun.com/training/certification/java/
Sun Professional Certifications
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Sun Certified Associate for the Java Platform, Standard Edition - New!
Sun Certified Programmer for the Java 2 Platform, Standard Edition J2SE 5.0 now available!
Sun Certified Developer for the Java 2 Platform, Standard Edition *
Sun Certified Web Component Developer for the Java 2 Platform,
Enterprise Edition
Sun Certified Business Component Developer for the Java 2
Platform, Enterprise Edition
Sun Certified Developer for Java Web Services
Sun Certified Enterprise Architect for the Java 2 Platform,
Enterprise Edition *
Sun Certified Mobile Application Developer for the Java 2 Platform,
Micro Edition
* An assignment needs to be completed
Shamelessly plagiarised directly from http://www.sun.com/training/certification/java/
TLA’s and Acronyms
SCJP – Sun Certified Java Programmer
SCJD – Sun Certified Java Developer
SCWCD – Sun Certified Web Component Developer
SCBCD – Sun Certified Business Component Developer
SCDJWS – Sun Certified Developer for Java Web Services
SMAD – Sun Certified Mobile Application Developer
J2SE – Java 2 Standard Edition
J2EE – Java 2 Enterprise Edition
J2ME – Java 2 Micro Edition
CX-310-035 – an apparently random number for SCJP 1.4
CX-310-055 – an apparently random number for SCJP 1.5
Other Certification Questions
Q. How long does my certification last?
A. This has changed a lot over the years. The current policy is that any certification gained after August the 1st,
2003 is valid forever! See http://www.sun.com/training/certification/faq/
Q. How do I choose which certification exam to study for?
A. Talk to somebody who has already certified and visit the following site:
http://www.sun.com/training/certification/objectives/index.xml
Q. I’ve decided to do the programmer certification, which one should I do? 4.0 or
5.0?
A. Version 5 is new, therefore it is harder to find resources (books and sites etc). As it becomes more
established more resources will be available.
Q. How long will it take me to study enough to sit the exam?
A. It depends on your experience, but I suggest you should earmark 3 months of committed part time study,
which at times can get quite intensive.
Q. Do I have to keep my certifications up-to-date?
A. Most people sit a certification exam and move onto a specialist exam rather than keeping their certification
versions current. However, there are Platform Upgrade exams and Sun recommend you keep your
certification up-to-date. See http://www.sun.com/training/certification/faq/
Part II
Sun Certified Java Programmer
Objectives and resources
SCJP - Facts and Figures
Duration
Number of
Questions
Pass Mark
Intensity
Cost
SCJP J2SE 4.0
CX-310-035
SCJP J2SE 5.0
CX-310-055
120 minutes
175 minutes
(2 hours)
(nearly 3 hours!)
61
72
52%
59%
(32 out of 61)
(43 out of 72)
High!
$150 USD
High!
$150 USD
Exam Objectives
Section
SCJP 4.0
SCJP 5.0
1
Declarations and Access Control
Declarations, Initialization
and Scoping
2
Flow control, Assertions, and Exception
Handling
Flow Control
3
Garbage Collection
API Contents
4
Language Fundamentals
Concurrency
5
Operators and Assignments
OO Concepts
6
Overloading, Overriding, Runtime Type and
Object Orientation
Collections / Generics
7
Threads
Fundamentals
8
Fundamental Classes in the java.lang
Package
9
The Collections Framework
Resources
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Books
Online Resources
Colleagues
Practice exams (beware, some might be
worse than useless)
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There are free ones
You can buy one from Sun
Books often come with a sample exam
Online resources
www.lanw.com/java/javacert/default.htm
www.aniyog.com/java/certification.htm
www.javaranch.com/mock.jsp
www.javaranch.com/maha/_Mock_Exams/_mock_exams.html
http://www.javaranch.com/mock.html
certification.about.com/od/freequestions/
www.michael-thomas.com/tech/java/java_info.htm
www.jchq.net/mockexams/exam2.htm
www.jchq.net/mockexams/exam1.htm
www.levteck.com/
www.sap-img.com/java/java-programmer-certification-mock-exam-no-answers.htm
www.akgupta.com/Java/mock_exam.htm
www.javaprepare.com/faq.html
http://www.jdiscuss.com/
http://bobcat.webappcabaret.net/javachina/faq/05.htm
http://java.sun.com/docs/books/jls/second_edition/html/j.title.doc.html
Books
The Good.
The certification book Java 2 Sun Certified Programmer &
Developer. Osborne ISBN 0-07-222684-6. It costs $114.99 so it's a
bit expensive! I've found it brilliant! The writing style is conversational and
at times funny!
The Bad
The other book I've tried is Exam Cram 2 - Java 2 Programmer. Que
ISBN 0-7897-2861-3. It costs $76.99. I think it is hopeless, if anybody
else is struggling with it, try the book above.
The Ugly
Ugly isn't as bad as bad! Java in a Nutshell O'Reilly ISBN 0-59600283-1. Costs $135.00. It isn't a certification book, but it is really
concise if heavy going (that's why I called it ugly). A great reference book
and excellent for a through, in-depth description of stuff that is relevant
for the exam.
Tricks and tips for study
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Try to get a group together to study with, it
makes it easier.
As you progress through your study you will begin to
get a ‘feeling’ for what the question is asking.
Read, practice, sit practice exams and discuss
with colleagues over and over again.
If you buy a certification book (recommended) be
prepared to read your chosen study book 3 times.
Ask your employer to pay for the exam. They
may pay or refund you if you pass the exam?
Tricks and tips for the Exam
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All questions are weighted equally
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So, answer all the ‘easy’ questions first
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You could spend 10 minutes on a difficult question and
get 2 marks.
Or you could spend 10 minutes on 5 questions and get
10 marks.
Mark questions for review if you have spent
too long on them and go back to them at the
end if you still have time.
Exam format
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The questions may include a code snippet or it may
be text question.
The questions are multi-choice.
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But don’t be fooled! It’s harder than “Who wants to be a
Millionaire”!
You are in a strange room with no windows, you’re
not allowed to talk to anybody and there are cameras
watching you all the time!
The exam is computer based:
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The computer is locked down
There is no internet access
There is a timer (so you know how much time you have left)
Example Question
This is a typical ‘easy’ question.
Which two are equal? (Choose two)
A.
32 / 4;
B.
(8 >> 2) << 4;
C.
2 ^ 5;
D.
128 >>> 2;
E.
(2 << 1) * (32 >> 3);
F.
2 >> 5
Reproduced without permission from the brilliant: Java 2 Sun Certified Programmer & Developer Osborne
Example Solution
It’s harder than Who wants to be a Millionaire, ‘cos:
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there are more than 4 answers to choose from
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you have to know all the answers to get the question right
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you don’t get a score of 25% if you just make up any old
answers
Which two are equal? (Choose two)
A.
32 / 4;
//
B.
(8 >> 2) << 4;
//
C.
2 ^ 5;
//
D.
128 >>> 2;
//
E.
(2 << 1) * (32 >> 3); //
F.
2 >> 5
//
8
32
7
32
16
0
Part III
Sample Questions
Literals
What's going on with this?
byte b = 7;
byte c = b + 7;
byte c += 7;
// gives a compile error
// this is OK
Literals
The difference is between literals and variables.
Number literals (1, 2, 3, to 9999 etc) can be implicitly
cast to bytes and the numeric operators (+, - / etc)
always return an int
And you can't automatically assign int variable into a
smaller primitive without casting (whereas you can with
a literal if it is small enough - the compiler knows)
Literals
byte b = 7;
byte c = b + 7;// gives a compile error
byte c += 7;
// this is OK
So:
byte b = 7;
c = b + 7;
byte c += 7;
This works 'cos literal 7 can be assigned to byte
This generates an ERROR! It returns an explicit int, which can't go into a
byte (I think the reason is that the compiler can never be entirely sure
what is in a variable, but it knows what a literal's value is)
// This is OK. Why? Because there is no int variable involved, only the
literal 7.
Logical Operators
What do you expect the output to be?
if (1>2 && 2>1 | true)
System.out.print("elephant tusk");
else
System.out.print("rhino");
Logical Operators
I expected the result to be derived like
this:
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1 is not greater than 2, so don't bother to
check 2 > 1.
Then do the OR, which returns true.
So we have "false or true".
Which gives true! So the answer should be
“elephant tusk”.
Logical Operators
The answer is not elephant tusk! The result is rhino! (Normally we'd
avoid this confusion by writing with brackets)
Before explaining the code lets check out this:
if (1>2 && 2>1 || true)
System.out.print("elephant tusk");
else
System.out.print("rhino");
The above returns elephant tusk (which is the intuitive result), which
roughly evaluates as:
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1 is not greater than 2, so don't bother to check 2 > 1.
Then do the OR, which returns true.
So we evaluate "false or true".
Which gives true!" as expected.
Logical Operators
Question: What is the difference between:
(1>2 && 2>1 || true)
and
(1>2 && 2>1 | true)
Logical Operators
Question: What is the difference between:
(1>2 && 2>1 || true)
and
(1>2 && 2>1 | true)
Answer: "Order of precedence". The relevant order of precedence is:
&
^
|
&&
||
Logical Operators
With (1>2 && 2>1 | true) the compiler does (what I call) a 'none evaluating
pass through the code'* and puts in imaginary brackets like this ((1>2) && (2>1 |
true)).
It does this because the compiler knows that the OR '|' keeps 2>1 and the true
together. The compiler will then evaluate the first half of the short circuit operator
&& (i.e. the 1>2) and decides seeing that it is false, that there is no more work to
do (see short circuit operators) and drops out of the condition and evaluates the
expression in the else block.
However for the expression (1>2 && 2>1 || true) the compiler again does the
'none evaluating pass through the code' puts imaginary brackets like this ((1>2 &&
2>1) || true).
This is because the compiler knows that && has a higher binding or precedent (call
it what you will). So it again checks the first half of the short circuit operator &&
(i.e. 1>2) and again decides to short circuit the second half of the &&. But the
second half is now only 2>1. It still has to do the or '||', which will make the whole
expression true.
Summary
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Certification Paradox – some people say the Java
Certified Programmer Certification is easy. Others say
it is one of the hardest industry certifications
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My view is that SJCP is not rocket science, but it is difficult
and there is a lot of it (that’s what makes it hard). It seems
to become easy when you start to learn the basics and learn
them well.
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There is no substitute for practice and experience
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For most people certification is tough but enormously
rewarding
Any Questions
Wyndham Ackroyd