1. Mrs. Yoast 1
Why Java

2. Mrs. Yoast 2
Why Java
 Java is simple
 No pointers
 Automatic memory management
 Simpler object-oriented techiques
 Streamlined syntax

3. Mrs. Yoast 3
Java Is Object-oriented
 Data can be modeled virtually as it
exists physically
 Objects can be assigned
properties (or data)
 Objects can be assigned behaviors
(or methods)
 Java uses inheritance
 Java uses polymorphism
 Java uses interfaces

4. Mrs. Yoast 4
Java is Distributed
 An application can be broken up
into multiple programs
 Each program can run on a
different computer than the other
pieces
 Each piece can talk to the others –
making a single “distributed”
application

5. Mrs. Yoast 5
Distributed Programs
Sample
Computer 1
Program 1
Web Server
Computer 2
Program 2
IBM PC
Computer 3
Program 3
Database
Server

6. Mrs. Yoast 6
Java Is Interpreted
 C++ Program
Source
Code
(prog.cpp)
Executable
Program
(prog.exe)
Executable Program
IBM PC
Text File
Machine
Language
Compiles
On PC

7. Mrs. Yoast 7
Why Won’t This Work?
Executable Program
UNIX Server
X

8. Mrs. Yoast 8
Java Is Interpreted
Source
Code
(prog.cpp)
Executable
Program
(prog.exe)
Executable Program
IBM PC
Text File
Compiles
On PC
Bytecode
Java Virtual Machine (Java to IBM PC)

9. Mrs. Yoast 9
So It Can Be Used on
Another Platform
Executable Program
IBM PC
Java Virtual Machine (Java to IBM PC)
This WILL Work

10. Mrs. Yoast 10
Java is Robust
 Java checks for errors early
 Java can’t write over memory
locations
 Java can catch runtime errors and
handle them

11. Mrs. Yoast 11
Java IS Secure
 Java is designed for networks
 Java is secure by design
Java is Platform-
independent
 Java programs run on any platform
that has a JVM
 Java applets run on most web
browsers.

12. Mrs. Yoast 12
Java is Multithreaded
 Multithreaded applications allow
several processes to execute
simultaneously
 Several clients can be handled
simultaneously

13. Mrs. Yoast 13
Java is Dynamic
 If one client is running part of a
Java class, and that class is
changed, the client will continue to
run the original version
 Subsequent clients will begin
running the new version while the
original client continues to run the
original class

14. Mrs. Yoast 14
Sample – Hello World
//Title: Hello World
//Version: 1.0
//Date: Aug. 15th, 2014
//Author: Mrs. Yoast
//Description: Hello World Program
public class HelloWorld
{
public static void main (String args[])
{
System.out.println(“Hello World.”);
}//ends main
}//ends HelloWorld