1. Road to Object Oriented Programming
Advanced programming ce244
Sharif University of Technology
Feb 2007
Sunday, February 18, 2007
Taha Abachi

2. Outline Deadlines Objects Object Oriented Languages
Editing your first java program
Compiling, running and debugging
Homework
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Taha Abachi

3. Deadlines By the end of the week you should have : The Java CD
Java installed on your machines
Edited, run, debugged your first Java programs without any trouble
Examined Java IDEs
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Taha Abachi

4. Objects Abstraction Definition Programming languages Problem space
State : internal data
Behavior : methods
Identity : each object can be uniquely distinguished from every other object
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5. Features of an Object An object has an interface
An object provides services
The hidden implementation
Data encapsulation
Reusing the implementation
Inheritance:reusing the interface
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6. Features of an Object (cont’d)
Sample object
Date :
Day : 1..31
Month : 1..12
Year :
Problems
Inconsistent data: no dependency to other fields
Day := 32
Inflexible representation
Date : longint Date := days passed after a specific date
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Taha Abachi

7. Features of an Object (cont’d)
Clients of the code
Yourself
Teammates
Customers
An infant programmer
Solution : Separating implementation form interface
More Secure and flexible
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Taha Abachi

8. Object Oriented Languages
Everything is an object.
A program is a bunch of objects telling each other what to do by sending messages.
Each object has its own memory made up of other objects.
Every object has a type.
All objects of a particular type can receive the same messages.
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Taha Abachi

9. Installing Java Install JDK Install Java Documentation
API(Application programming Interface)
Set Environment variables
Choose a text editor
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10. Java Characteristics Portability : Interpreting : JVM
compile programs to a intermediary format called JBC
C:\>javac HelloWorld.java to produce HelloWorld.class
Interpreting : JVM
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Taha Abachi

11. Portability
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12. Java is Object Oriented
Every thing in Java is an Object.
Objects in OOP mirror the properties and behavior of the real world objects.
They have their own set of data and functions (called method) that operate on these data.
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Taha Abachi

13. First Program in Java Use a text editor Write down your program
Java is case sensitive
Compile your program
Run
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Taha Abachi

14. HelloWorld public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello World"); }
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Taha Abachi

15. Java program files
Each class is saved in a file of the same name with java extension.
Note java is case sensitive language, even as far as the class file names are concerned.
The Hello class should be saved in a file called HelloWorld.java class .
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Taha Abachi

16. Syntax Highlighting public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello World"); }
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17. The method main ( )
The main() method is the point where a Java program starts running.
Any executable Java class must have the main() method in this specific format:
public static void main(String[ ] args){
………….. }
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Taha Abachi

18. Time to compile Use javac command to compile your java programms :
C:\> javac HelloWorld.java
HelloWorld.class (JBC file) is created
You may face some errors
Correct erroneous parts and compile again
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Taha Abachi

19. Run The Java command is used to run the class (JBC) file:
c:\> Java HelloWorld
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20. You are a Java programmer NOW!
Congratulations
You are a Java programmer NOW!
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Taha Abachi

21. Java Development Environments
Sun's JDK is not an environment.
Sun's Java Workshop
Microsoft's Visual J++
Symantec's Cafe
Borland's J Builder
Metrowerks' Code Warrior
Tek-Tools' Kawa.
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Taha Abachi

22. Java Development Environments
My candidates :
IntelliJ IDEA
Eclipse
Textpad
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Taha Abachi

23. Homework Install Java properly Write and Test you first Java program
Design an object oriented environment for manipulating geometrical shapes :
Different subtypes (square, circle, etc.)
Common characteristics (fields & methods)
Particular characteristics
Use UML (Unified Modeling Language) notation
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Taha Abachi

24. Questions?
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Taha Abachi