Transcript The Sun’s Java Certification and its possible role in the

The Sun’s Java Certification
and its Possible Role in the
Joint Teaching Material
Nataša Ibrajter
Faculty of Science
Department of Mathematics and Informatics
Novi Sad
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Contents
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Kinds of Sun Certified Exams
Why Become Java 2 Certified?
Developer's Certification Exam (SCJD)
The Programmer’s Exam (SCJP)
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Some Characteristic Questions
A Proposal for the Joint Java Course
The NS Experience
Impact on the Joint Material
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Kinds of Sun Certified Exams
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Kinds of Sun Certified Exams
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Sun Certified Programmer (SCJP)
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CX-310-035 Programmer’s Exam
Sun Certified Developer (SCJD)
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CX-310-252A Developer’s Programming
Assignment
CX-310-027 Developer’s Essay Exam
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Why Become Java 2 Certified?
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It provides proof of professional achievement.
It increases one’s marketability.
It provides greater opportunity for
advancement in one’s field.
It is increasingly found as a requirement for
some types of advanced training.
It raises customer confidence in you and your
company’s services.
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Developer's Certification Exam
(SCJD)
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It consists of two parts:
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a project assignment and
a follow-up exam
The assignment describes a task that
starts with some code supplied with a
project description. Person who takes
the exam is supposed to finish the
project.
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Developer's Certification Exam
(SCJD)
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The follow-up exam has at least three
aspects:
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Java's features and libraries,
knowledge and understanding of one's own
classes,
defending the choices one made writing
code.
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Developer's Certification Exam
(SCJD)
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I/O streams
Swing
The AWT event
model
Object serialization
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RMI
javadoc
Packages
Threads
Interfaces
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The Programmer’s Exam (SCJP)
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Language fundamentals
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Source files
Keywords and identifiers
Primitive data types
Literals
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boolean literals
char literals
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The Programmer’s Exam (SCJP)
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Arrays
Class fundamentals
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integral literals
floating-point literals
string literals
the main() method
variables and initialization
Argument passing: by reference or by
value
Garbage collection
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The Programmer’s Exam (SCJP)
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Operators and assignments
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Evaluation order
The unary operators
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++ and -+ and ~
!
cast operator
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The Programmer’s Exam (SCJP)
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The arithmetic operators
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* and /
%
+ and arithmetic error conditions
The shift operators: >>, << and >>>
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fundamentals of shifting
shifting negative numbers
arithmetic promotion of operands
reduction of the right operand
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The Programmer’s Exam (SCJP)
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The comparison operators
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<, <=, > and >=
the instanceof operator
the equality comparison operators: == and !=
Logical operators: &&, || and !
Short-circuiting
Bitwise operators: &, |, ^ and ~
The conditional operator: ? :
The assignment operator
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The Programmer’s Exam (SCJP)
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Modifiers
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Modifier overview
The access modifiers
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public
private
default
protected
subclasses and method privacy
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The Programmer’s Exam (SCJP)
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Other modifiers
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final
abstract
static
static initilalizers
native
transient
synchronized
volatile
Modifiers and features
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The Programmer’s Exam (SCJP)
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Converting and casting
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Explicit and implicit type changes
Primitives and conversion
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primitive conversion: assignment
assignment conversion, narrower primitives and
literal values
primitive conversion: method call
primitive conversion: arithmetic promotion
Primitives and casting
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The Programmer’s Exam (SCJP)
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Object reference conversion
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object reference assignment conversion
object method-call conversion
Object reference casting
Flow control, assertions and exception
handling
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The loop constructs
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while
do
for
break and continue statements in loops
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The Programmer’s Exam (SCJP)
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Selection statements
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Exceptions
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if-else construct
switch construct
flow of control in exception conditions
throwing exceptions
Assertions
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assertions and compilation
runtime enabling of assertions
using assertions
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The Programmer’s Exam (SCJP)
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Objects and classes
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Benefits of object-oriented implementation
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Implementing OO relationships
Overloading and overriding
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encapsulation
re-use
overloading method names
method overriding
Constructors and subclassing
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overloading constructors
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The Programmer’s Exam (SCJP)
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Inner classes
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the enclosing this reference and construction of inner
classes
member classes
classes defined inside methods
Threads
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Thread fundamentals
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what a thread executes
when execution ends
thread states
thread priorities
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The Programmer’s Exam (SCJP)
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Controlling threads
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yielding
suspending
sleeping
blocking
monitor states
scheluduling implementation
Monitors, wait and notify
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the object lock and synchronization
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The Programmer’s Exam (SCJP)
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wait and notify
the class lock
beyond the pure model
deadlock
another way to synchronize
java.lang and java.util packages
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The Object class
The Math class
The wrapper classes
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The Programmer’s Exam (SCJP)
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Strings
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the String class
the StringBuffer class
string concatenation easy way
The collections API
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collection types
collections, equality and sorting
the hashCode method
collection implementations in the API
collections and code maintenance
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Some Characteristic Questions
Language fundamentals
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Consider the following line of code:
int[] x = new int[25];
After execution, which statements are
true? Choose all that apply.
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2.
3.
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x[24] is 0.
x[24] is undefined.
x[25] is 0.
x[0] is null.
x.length is 25.
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Some Characteristic Questions
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Operators and assignments
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What results from the following fragment
of code?
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5.
6.
int x = 1;
String [] names = {“Fred”, “Jim”, “Sheila”};
names[--x] += “.”;
for(int i =0; i<names.length; i++){
System.out.println(names[i]);
}
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Some Characteristic Questions
1.
2.
3.
4.
5.
The output includes Fred. with a trailing period.
The output includes Jim. with a trailing period.
The output includes Sheila. with a trailing
period.
None of the outputs show a trailing period.
An ArrayIndexOutOfBoundsException is thrown.
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Some Characteristic Questions
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Modifiers
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Given the following code and making no other
changes, which combination of access modifiers
(public, protected or private) can legally be placed
before aMethod() on line 2 and be placed before
aMethod() on line 6?
1. class SuperDuper{
2. void aMethod(){}
3. }
4.
5. class Sub extends SuperDuper{
6. void aMethod(){}
7. }
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Some Characteristic Questions
1.
2.
3.
4.
5.
line
line
line
line
line
2:
2:
2:
2:
2:
public; line 6: private
protected; line 6: private
default; line 6: private
private; line 6: protected
public; line 6: protected
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Some Characteristic Questions
Converting and casting
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Will the following code compile?
1. byte b = 2;
2. byte b1 = 3;
3. b = b * b1;
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Yes
2.
No
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Some Characteristic Questions
class hierarchy for next question
Animal
Mammal
Dog
Cat
implements
Washer
Raccoon
implements
Washer
SwampThing
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Some Characteristic Questions
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Consider the following code:
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3.
4.
5.
6.
Dog
rover, fido;
Animal anim;
rover = new Dog();
anim = rover;
fido = (Dog)anim;
Which of the following statements are
true? Choose one.
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Some Characteristic Questions
1.
2.
3.
4.
5.
Line 5. will not compile.
Line 6. will not compile.
The code will compile but will throw an
exception at line 6.
The code will compile and run.
The code will compile and run, but the cast in
line 6 is not required and can be eliminated
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Some Characteristic Questions
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Flow control, assertions and exception
handling
Consider the following code:
1.
2.
3.
4.
5.
6.
7.
8.
for(int i=0; i<2; i++){
for(int j=0; j<3; j++){
if(i == j){
continue;
}
System.out.println(“i = ”+i+” j = ”+j);
}
}
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Some Characteristic Questions
Which lines would be part of the output?
Choose all that apply.
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2.
3.
4.
5.
6.
i
i
i
i
i
i
=0
=0
=0
=1
=1
=1
j
j
j
j
j
j
=
=
=
=
=
=
0
1
2
0
1
2
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Some Characteristic Questions
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Objects and classes
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Considering this class:
1. public class Test1{
2. public float aMethod(float a, float b){}
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4. }
Which of the following methods would be
legal if added (individually) at line 3?
Choose all that apply.
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Some Characteristic Questions
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2.
3.
4.
5.
public int aMethod(int a, int b){}
public float aMethod(float a, float b){}
public float aMethod(float a, float b, int c)
throws Exception{}
public float aMethod(float c, float d){}
private float aMethod(int a, int b, int c){}
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Some Characteristic Questions
Threads
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A Java monitor must either extend
Thread or implement Runnable.
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2.
True
False
The java.lang and java.util packages
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In the following code fragment, line 4 is
executed.
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Some Characteristic Questions
1. String s1 = “xyz”;
2. String s2 = “xyz”;
3. if (s1 == s2)
4. System.out.println(“4”);
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True
2.
False
1. String s1 = “xyz”;
2. String s2 = new String(s1);
3. if (s1 == s2)
4. System.out.println(“4”);
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True
2.
False
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A Proposal for the Joint Java
Course
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Part I - Imperative Java programming
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Introduction (in case that Java is the first
programming language)
The language overview (elements of Java)
Simple data types
Expressions and control structures
Structured data types: arrays
Methods
Recursion
Complex examples with arrays (searching and
sorting)
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A Proposal for the Joint Java
Course
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Part II - OOP in Java and advanced topics
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Introduction to OOP (OOP in general, place of
Java, its development...)
Basic notations of OOP
Classes and objects. Class methods and variables.
Object creation
Inheritance and polymorphism
Concatenated list structures
Trees
Packages
Interfaces
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A Proposal for the Joint Java
Course
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Abstract classes
Introduction to UML
Exceptions
GUI development
Class libraries, Java Collection Framework
Reflection in Java
Threads
Basic notions of WWW
Applets
Remote Method Invocation
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A Proposal for the Joint Java
Course
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Part III - Environments for Java
programming
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Usage of J2SE JDK 1.xx
Part IV - Java programming at large
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Introducing SE principles in Java
programming
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The NS Experience
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Our students are obliged to take part in not
less than 70% of practical exercises, not less
than 50% of exercises and not less than 30%
of lectures.
The exam consists of the practical part (which
is taken during the practical exercises) and of
the test.
The Java certification is used as a template
for the test.
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The NS Experience
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Students mostly show weakness in
understanding how Java solves OOP issues
like overriding, overloading, program flow etc,
not in understanding theoretical basics of
OOP.
The test tests practical knowledge in Java,
not the theoretical knowledge in OOP.
If the students missed to study some aspect
of a problem taking practical part of the
exam, the test forces them to restudy the
problem.
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The NS Experience
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70% of Programmer’s Exam questions
covered by our course
More than 90% excluding major sections like
threads and assertions
Therefore, we cannot ‘blindly’ use any of the
questions
Should we change our course to cover more
questions?
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Suggestion: No
However, some compatibility useful
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Impact on the Joint Material
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From our experience: without references to
the Java Certification we cover about
70%/90% of the questions
For the creation of the Joint Material,
occasional references to Java Certification
exam questions are useful to
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see what the industry thinks is important
check for omissions
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