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Part I : Chapter 01
Introduction to Java Programming
1
Objectives
• To learn about Java and its history.
• To create, compile, and run Java programs.
• To understand the Java runtime environment.
• To write a simple Java application.
2
History of Java
• Green Project
• Developed by a team led by James
Gosling at Sun Microsystems.
• 1991: Oak (use in embedded consumer electronic
application)
• 1995: Java (redesigned for developing Internet
applications)
James Gosling and Duke
http://java.sun.com/people/jag/
3
History of Java
•
This is a snapshot taken at a barbecue that James Gosling threw for
some of the folks associated with the Green Team. From left to right
they are: Al Frazier, Joe Palrang, Mike Sheridan, Ed Frank, Don
Jackson, Faye Baxter, Patrick Naughton, Chris Warth, James Gosling,
Bob Weisblatt, David Lavallee, and Jon Payne. Missing in action:
Cindy Long, Chuck Clanton, Sheueling Chang, and Craig Forrest.
•
(http://java.sun.com/features/1998/05/birthday.html)
4
Java Version History
Version
Code-Name
Release Date
JDK 1.1.4
Sparkler
Sept 12, 1997
JDK 1.1.5
Pumpkin
Dec 3, 1997
JDK 1.1.6
Abigail
April 24, 1998
JDK 1.1.7
Brutus
Sept 28, 1998
JDK 1.1.8
Chelsea
April 8, 1999
J2SE 1.2
Playground
Dec 4, 1998
J2SE 1.2.1
(none)
March 30, 1999
J2SE 1.2.2
Cricket
July 8, 1999
J2SE 1.3
Kestrel
May 8, 2000
J2SE 1.3.1
Ladybird
May 17, 2001
J2SE 1.4.0
Merlin
Feb 13, 2002
J2SE 1.4.1
Hopper
Sept 16, 2002
J2SE 1.4.2
Mantis
June 26, 2003
J2SE 5.0 (1.5.0)
Tiger
Sept 29, 2004
Java SE 6.0 (1.6.0)
Mustang
December 11, 2006
Java SE 6 Update 14
-
May 28, 2009
Java SE 7.0 (1.7.0)
Dolphin
Plan to release in 2010
5
Characteristics of Java
• Java is simple.
• Java is Object-Oriented
• Java is Case-sensitive
• Java is Interpreted (Write-Once, Run-Anywhere)
• Java is Robust
• Java is Multithreaded
• Java can be manipulated in two ways:
Application and Applet
6
Platform of Java Technologies
• Java, Micro Edition
(JMETM technology)
• Java, Standard Edition
(JSETM technology)
• Java, Enterprise Edition
(JEETM technology)
7
Platform of Java Technologies
http://java.sun.com/java2/whatis/index.html
8
Architecture of Java
Java Programming Language
Java class file
Java API
Java platform
Java Virtual Machine (Java VM)
Computer System
API = Application Programming Interface
9
Typical Java Development Environment
Java
source code
.java
Java compiler
(javac)
.class Java Interpreter
(java)
HTML page
.html
Appletviewer
or
Browser
Application
Applet
10
Typical Java Development
Environment
Editor
Compiler
Disk
Class Loader
Bytecode Verifier
JVM
Primary Memory
11
Style of Java Programming
• Java application
– Run in text mode
– Run in GUI mode
• Java applet
<html>
<applet code=“myApplet.class” width=…
height=…>
</applet>
</html>
12
Anatomy of the Application Program
•
•
•
•
•
•
•
•
Comments
Reserved Words
Modifiers
Statements
Blocks
Classes
Methods
The main method
13
Java Keywords
•
•
•
•
•
•
•
•
•
•
•
abstract boolean break
catch
char
class
default
do
double
false
final
finally
goto
if
implementation
int
interface
long
null
package
private
return
short
static
synchronized
this
transient true
try
while
bytecase
const
continue
elseextend
floatfor
import
instanceof
native
new
protected public
super
switch
throw
thows
voidvolatile
14
The First Java Application Example
// A first program in Java
Begin class definition
public class Welcome
{
public static void main ( String args[] )
{
System.out.println(“Welcome to Java
Programming”);
}
}
Declaration of main method
Arguments of main method
15
The First Java Application Example
• System.out is a standard output object
to display text in text mode
• println is a method of System.out
• To call a method, use . between a class /
object’s name and the method
– System.out.println(“…”);
– car.getLevel();
16
The First Java Application Example
• Save as a name of Welcome.java
• compile Welcome.java
– javac Welcome.java
– See the output
• run
– java Welcome
– See the output
17
Java Application Example II
// Printing multiple lines in a dialog box
import javax.swing.JOptionPane;
public class Welcome2
{
public static void main (String args[] ) {
JOptionPane.showMessageDialog ( null,
“Welcome\nto\nJava\nProgramming!”);
System.exit(0);
// terminate the program
}
}
18
Java Application Example II
• import javax.swing.JOptionPane; to call a class named
JOptionPane
into the class.
• JOptionPane.showMessageDialog ( null,
“Welcome\nto\nJava\nProgramming!”);
call a method named showMessageDialog of JOptionPane class.
• System.exit(0); is applied as the last command of
the class to return resource to the system.
19
Java Application Example II
• Save the file as Welcome2.java
• compile Welcome2.java
– javac Welcome2.java
– See the output
• run
– java Welcome2
– See the output
20
The First Applet
// The first applet in Java
import javax.swing.JApplet;
import java.awt.Graphics;
inheritance
public class WelcomeApplet extends JApplet {
public void paint ( Graphics g ) {
g.drawString(“Welcome to Java Programming”, 25, 25);
}
}
21
The First Applet
• Save the file as WelcomeApplet.java
• compile WelcomeApplet.java
– javac WelcomeApplet.java
– See the result
• run
– Create a html file to call the applet
<html>
<applet code=“WelcomeApplet.class” width=300 height=30>
</applet>
</html>
– Save the .html file. Name the file in any name such as
welcome.html
– run by typing appletviewer welcome.html
– Or call the .html in any browser program.
22
End of Chapter01
Introduction to Java
23
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