1. Chapter 1: Introduction
Object-Oriented Program Development Using Java: A Class-Centered Approach

2. Programming Languages
Computer program
A self-contained set of instructions and data used to operate a computer to produce specific results
Also called software
Programming is the process of developing and writing a program
A programming language is a set of instructions that can be used to construct a program
Object-Oriented Program Development Using Java: A Class-Centered Approach

3. Programming Languages (continued)
Low-level languages:
Machine language
Assembly language
Object-Oriented Program Development Using Java: A Class-Centered Approach

4. Programming Languages (continued)
High-level languages:
Use instructions that resemble natural languages
Can be run on a variety of computer types
Examples:
Pascal
Visual Basic C
C++
Java
Object-Oriented Program Development Using Java: A Class-Centered Approach

5. Programming Languages (continued)
Source program
Programs written in a computer language
Interpreted language
Each statement is translated individually and executed immediately upon translation
Compiled language
All statements are translated as a complete unit before any one statement is executed
Object-Oriented Program Development Using Java: A Class-Centered Approach

6. Programming Languages (continued)
Java is both:
Compiled
Interpreted
Java Virtual Machine
Software program that can read bytecode produced by the compiler and execute it
Object-Oriented Program Development Using Java: A Class-Centered Approach

7. Object-Oriented Program Development Using Java: A Class-Centered Approach

8. Procedure and Object Orientations
Procedure-oriented language
Available instructions are used to create self-contained units
Object-oriented language
Program must first define objects it will be manipulating
Java is object-oriented
Object-Oriented Program Development Using Java: A Class-Centered Approach

9. The Development of Java
History:
Fortran
COBOL
BASIC
Pascal
C++
Java
Object-Oriented Program Development Using Java: A Class-Centered Approach

10. The Development of Java (continued)
Web browser
A program located and run on a user’s computer to display Web pages
Java can run from a Web browser
Java provides:
Cross-platform compatibility
Write-once-run-anywhere capability
Object-Oriented Program Development Using Java: A Class-Centered Approach

11. Object-Oriented Program Development Using Java: A Class-Centered Approach

12. Objects and Classes Objects
Part of the Java programming language as component types
Can be custom tailored by programmers
Programmers can define custom objects
Object-Oriented Program Development Using Java: A Class-Centered Approach

13. A Class Is a Plan
The structure for a class of objects must be created at the start of the programming process
Class
Explicitly written plan
Complete set of parts and instructions needed to create items
Object-Oriented Program Development Using Java: A Class-Centered Approach

14. From Recipe to Class Data declaration section Methods section
Description of data to be used
Methods section
Defines how to combine data components to produce desired result
Object-Oriented Program Development Using Java: A Class-Centered Approach

15. Object-Oriented Program Development Using Java: A Class-Centered Approach

16. A First Java Class A class consists of a class header line and a body
The class header line includes the words public class nameofclass
Class body
Encloses data and methods that make up class
Typically two sections of code:
The types of data that will be used
Procedures that will be used on the data
Object-Oriented Program Development Using Java: A Class-Centered Approach

17. Object-Oriented Program Development Using Java: A Class-Centered Approach

18. Object-Oriented Program Development Using Java: A Class-Centered Approach

19. Constructing a Java Program
Programs can use existing classes
A Java program is:
Considered an executable applications program
A class that must contain a method named main
Object-Oriented Program Development Using Java: A Class-Centered Approach

20. The main Method public static void main(String [] args)
Every program must have the main method
Methods begin and end with {}
Object-Oriented Program Development Using Java: A Class-Centered Approach

21. Object-Oriented Program Development Using Java: A Class-Centered Approach

22. Reserved Words Predefined by programming language for special purpose
Can only be used in specified manner for intended purpose
Also called keywords in Java
Object-Oriented Program Development Using Java: A Class-Centered Approach

23. Object-Oriented Program Development Using Java: A Class-Centered Approach

24. Standard Identifiers Java-defined words that have predefined purpose
Can be redefined by a programmer
Names of classes and methods provided in Java
A good programming practice is to only use standard identifiers for their intended purpose
Object-Oriented Program Development Using Java: A Class-Centered Approach

25. Object-Oriented Program Development Using Java: A Class-Centered Approach

26. Identifiers Programmer-supplied words
Can be made up of any combination of:
Letters
Digits
Underscores (_)
Dollar signs ($)
Common practice:
The first letter of each word, starting with the second word in a multiword identifier, is capitalized
Object-Oriented Program Development Using Java: A Class-Centered Approach

27. Rules for Identifiers in Java
The first character of the identifier cannot be a digit
Only letters, digits, underscores, and dollar signs may follow the initial character
Blank spaces are not allowed
Identifiers cannot be reserved words
Maximum number of characters in the identifier name is unlimited
Object-Oriented Program Development Using Java: A Class-Centered Approach

28. What Is Syntax?
Set of rules for formulating grammatically correct language statements
Program has proper form specified for compiler
Individual statement or program can be syntactically correct and still be logically incorrect
Object-Oriented Program Development Using Java: A Class-Centered Approach

29. The PrintStream Class’s print() and println() Methods
print() and println() are in the PrintStream class and are print methods:
Display data to standard output
Package
One or more individual classes stored in the same directory
Object-Oriented Program Development Using Java: A Class-Centered Approach

30. The PrintStream Class’s print() and println() Methods (continued)
General syntax:
objectName.print(data)
System.out.print("Hello World!");
Parameters
Items are passed to a method through parentheses
Also called
Arguments
Actual arguments
Object-Oriented Program Development Using Java: A Class-Centered Approach

31. The PrintStream Class’s print() and println() Methods (continued)
Prints output only
println()
Prints output and appends new line \n
Newline escape character
Object-Oriented Program Development Using Java: A Class-Centered Approach

32. Java Documentation Sources for documentation:
http//java.sun.com/docs/search.html
Hard copy books:
The Java Class Libraries
JFC Swing Tutorial
Object-Oriented Program Development Using Java: A Class-Centered Approach

33. The System Class
Provides methods for examining system-related information, such as:
Name of the operating system
Java version number
Supports basic input and output services
Object-Oriented Program Development Using Java: A Class-Centered Approach

34. Programming Style Java ignores whitespace Proper programming style:
Makes programs easy to read
Minimizes mistakes
Proper style for main method:
public static void main(String[] args) {
program statements in here; }
Object-Oriented Program Development Using Java: A Class-Centered Approach

35. Comments Spans lines */ Explanatory remarks made within a program
Comment types in Java:
Line
Block
// Line comment
/* Block comment
Spans lines */
Object-Oriented Program Development Using Java: A Class-Centered Approach

36. Common Programming Errors
Knowing about common errors helps programmers avoid them
Most common errors:
Forgetting to save program with same file name as class name used within the program
Omitting a semicolon at the end of each statement
Forgetting \n to indicate a new line
Object-Oriented Program Development Using Java: A Class-Centered Approach