The Sun’s Java Certification and its Possible Role in the Joint Teaching Material

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The Sun’s Java Certification and its

Possible Role in the Joint Teaching Material

Nataša IbrajterFaculty of Science

Department of Mathematics and InformaticsNovi Sad

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Contents Kinds of Sun Certified Exams Why Become Java 2 Certified? Developer's Certification Exam (SCJD) The Programmer’s Exam (SCJP)

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

Sun Certified Programmer (SCJP) CX-310-035 Programmer’s Exam

Sun Certified Developer (SCJD) CX-310-252A Developer’s

Programming Assignment CX-310-027 Developer’s Essay Exam

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Why Become Java 2 Certified? 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) It consists of two parts:

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)

The follow-up exam has at least three aspects: 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)

I/O streams Swing The AWT event

model Object serialization

RMI javadoc Packages Threads Interfaces

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The Programmer’s Exam (SCJP)

Language fundamentals Source files Keywords and identifiers Primitive data types Literals

boolean literals char literals

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The Programmer’s Exam (SCJP)

integral literals floating-point literals string literals

Arrays Class fundamentals

the main() method variables and initialization

Argument passing: by reference or by value

Garbage collection

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The Programmer’s Exam (SCJP)

Operators and assignments Evaluation order The unary operators

++ and -- + and - ~ ! cast operator

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The Programmer’s Exam (SCJP)

The arithmetic operators * and / % + and - arithmetic error conditions

The shift operators: >>, << and >>> fundamentals of shifting shifting negative numbers arithmetic promotion of operands reduction of the right operand

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The Programmer’s Exam (SCJP)

The comparison operators <, <=, > 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)

Modifiers Modifier overview The access modifiers

public private default protected subclasses and method privacy

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The Programmer’s Exam (SCJP)

Other modifiers final abstract static static initilalizers native transient synchronized volatile

Modifiers and features

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The Programmer’s Exam (SCJP) Converting and casting

Explicit and implicit type changes Primitives and conversion

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)

Object reference conversion object reference assignment conversion object method-call conversion

Object reference casting Flow control, assertions and exception

handling The loop constructs

while do for break and continue statements in loops

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The Programmer’s Exam (SCJP)

Selection statements if-else construct switch construct

Exceptions flow of control in exception conditions throwing exceptions

Assertions assertions and compilation runtime enabling of assertions using assertions

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The Programmer’s Exam (SCJP) Objects and classes

Benefits of object-oriented implementation

encapsulation re-use

Implementing OO relationships Overloading and overriding

overloading method names method overriding

Constructors and subclassing overloading constructors

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The Programmer’s Exam (SCJP)

Inner classes the enclosing this reference and construction of

inner classes member classes classes defined inside methods

Threads Thread fundamentals

what a thread executes when execution ends thread states thread priorities

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The Programmer’s Exam (SCJP)

Controlling threads yielding suspending sleeping blocking monitor states scheluduling implementation

Monitors, wait and notify the object lock and synchronization

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The Programmer’s Exam (SCJP)

wait and notify the class lock beyond the pure model deadlock another way to synchronize

java.lang and java.util packages The Object class The Math class The wrapper classes

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The Programmer’s Exam (SCJP)

Strings the String class the StringBuffer class string concatenation easy way

The collections API 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

Consider the following line of code:int[] x = new int[25];

After execution, which statements are true? Choose all that apply.

1. x[24] is 0.2. x[24] is undefined.3. x[25] is 0.4. x[0] is null.5. x.length is 25.

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Some Characteristic Questions Operators and assignments

What results from the following fragment of code?1. int x = 1;2. String [] names = {“Fred”, “Jim”,

“Sheila”};3. names[--x] += “.”;4. for(int i =0; i<names.length; i++){5. System.out.println(names[i]);6. }

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Some Characteristic Questions

1. The output includes Fred. with a trailing period.

2. The output includes Jim. with a trailing period.

3. The output includes Sheila. with a trailing period.

4. None of the outputs show a trailing period.5. An ArrayIndexOutOfBoundsException is

thrown.

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Some Characteristic Questions Modifiers

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. line 2: public; line 6: private2. line 2: protected; line 6: private3. line 2: default; line 6: private4. line 2: private; line 6: protected5. line 2: public; line 6: protected

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Some Characteristic Questions Converting and casting

Will the following code compile?1. byte b = 2;2. byte b1 = 3;3. b = b * b1;1. Yes2. No

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Some Characteristic Questions

class hierarchy for next question

Animal

Mammal

Dog

Catimplements

Washer

Raccoonimplements

WasherSwampThing

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Consider the following code:1. Dog rover, fido;2. Animal anim;3. 4. rover = new Dog();5. anim = rover;6. fido = (Dog)anim;

Which of the following statements are true? Choose one.

Some Characteristic Questions

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Some Characteristic Questions

1. Line 5. will not compile.2. Line 6. will not compile.3. The code will compile but will throw an

exception at line 6.4. The code will compile and run.5. 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 Flow control, assertions and

exception handlingConsider the following code:

1. for(int i=0; i<2; i++){2. for(int j=0; j<3; j++){3. if(i == j){4. continue;5. }6. System.out.println(“i = ”+i+” j = ”+j);7. }8. }

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Some Characteristic Questions

Which lines would be part of the output? Choose all that apply.

1. i =0 j = 02. i =0 j = 13. i =0 j = 24. i =1 j = 05. i =1 j = 16. i =1 j = 2

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Some Characteristic Questions Objects and classes

Considering this class:1. public class Test1{2. public float aMethod(float a, float b){}3. 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

1. public int aMethod(int a, int b){}2. public float aMethod(float a, float b){}3. public float aMethod(float a, float b, int c)

throws Exception{}4. public float aMethod(float c, float d){}5. private float aMethod(int a, int b, int c){}

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Some Characteristic Questions Threads

A Java monitor must either extend Thread or implement Runnable.

1. True2. False

The java.lang and java.util packages

In the following code fragment, line 4 is executed.

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Some Characteristic Questions1. String s1 = “xyz”;2. String s2 = “xyz”;3. if (s1 == s2) 4.

System.out.println(“4”);1. True2. False

1. String s1 = “xyz”;2. String s2 = new

String(s1);3. if (s1 == s2) 4.

System.out.println(“4”);1. True2. False

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A Proposal for the Joint Java Course Part I - Imperative Java programming

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 Part II - OOP in Java and advanced topics

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

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

Part III - Environments for Java programming Usage of J2SE JDK 1.xx

Part IV - Java programming at large Introducing SE principles in Java

programming

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The NS Experience 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 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 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? Suggestion: No However, some compatibility useful

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Impact on the Joint Material 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 see what the industry thinks is important check for omissions