This document provides an introduction to the Java programming language. It discusses key Java concepts like high-level vs low-level languages, common programming languages, how Java works by compiling to bytecode and using a virtual machine, and why Java was created. It also includes a simple "Hello World" Java program example to demonstrate Java syntax and how to compile and run a Java program.

1. Lesson1: JAVA
Computer Fundamentals I
INTRODUCTION TO JAVA PROGRAMMING

2. HARDWARE AND SOFTWARE
INTRODUCTION TO JAVA PROGRAMMING

3. What is Programming Language
• High Level Language & Low Level
Language
C++, C, FORTRAN, PASCAL
Assembly Language or Machine Language
• High Level Language Better or Low Level
Language.
INTRODUCTION TO JAVA PROGRAMMING

4. Programming languages: A Review
• FORTRAN • Ada
• COBOL • SQL
• BASIC • Lisp
• Z80 assembler • Prolog
• IBM 360 assembler • Eiffel
• PL1 • HTML
• SL1 • JavaScript
• C • Java
• Pascal • Jess
• SNOBOL
INTRODUCTION TO JAVA PROGRAMMING

5. Discussion Points
• Different levels: high - low
• Different implementations: interpreted, compiled
• Different paradigms: procedural, declarative,
object oriented
• Different target domains: data processing,
scientific, database manipulation, string
manipulation, logic, general purpose …
• Different ages: modern/ old fashioned; longevity
• Different language features/ constructs
INTRODUCTION TO JAVA PROGRAMMING

6. Common Grounds
• Handle data: variables
• Handle flow of control:
– sequence, selection, iteration
• Shared code: sub routines
• Data structures: arrays
• File handling
INTRODUCTION TO JAVA PROGRAMMING

7. Interpreting and Compiling
NOTE : JAVA do both, Interpreting and Compiling
INTRODUCTION TO JAVA PROGRAMMING

8. How JAVA Works
Portability can be Achieved this Way
INTRODUCTION TO JAVA PROGRAMMING

9. Why JAVA
• Simple and clean
• Object oriented
• Portable/ platform independent
• Robust
• Secure
• Multi-threaded
• Dynamic
• ++
INTRODUCTION TO JAVA PROGRAMMING

10. Program
• A program is a sequence of instructions that specifies
how to perform a computation.
BASIC Operations in Program:
• Input
• Output
• Mathematical Operations
• Testing
• Repetition
“Programming can also be described as the process of
breaking a large, complex task up into smaller and smaller
subtasks until eventually the subtasks are simple enough to
be performed with one of these basic operations.”
INTRODUCTION TO JAVA PROGRAMMING

11. Debugging
• Bugs and Errors
• Types of Errors
Compile Time Errors
Run Time Errors
Logic and Semantic Error
• Experimental Debugging
INTRODUCTION TO JAVA PROGRAMMING

12. A First Program
• Print “Hello World” to the console
/*
* HelloWorld.java
*
* Created on 19 Sep 2010, 17:56
*/
class HelloWorld {
public static void main (String args[]) {
System.out.println("Hello World!");
}
}
INTRODUCTION TO JAVA PROGRAMMING

13. First Steps...
• A Java application is made up of a
collection of classes
• Normally, one (& only one) of these classes
should have a method called main
• Console output can be achieved using:
System.out.print(“a string”);
or
Err or
println
or a
variable
INTRODUCTION TO JAVA PROGRAMMING

14. Compiling First Program
• The file name of this program is:
HelloWorld.java
• To compile the program, type:
javac HelloWorld.java
• To run the program, type:
java HelloWorld
• Output should be:
Hello World!
INTRODUCTION TO JAVA PROGRAMMING

15. The JAVA Virtual Machine
• Java is compiled into an intermediate form
(bytecode)
• These are the .class files produced by javac
• The bytecode is interpreted at runtime by
the Java Virtual Machine
• Java compiled on one machine (type) can be
executed on another (type)
INTRODUCTION TO JAVA PROGRAMMING

16. Standard Java Tools (Java 2 SDK)
• javac - the compiler
• java - the launcher for Java apps
• javadoc - API documentation generator
• appletviewer - run & debug applets without
a browser
• jar - manage Java Archive (JAR) files
• jdb - Java debugger
• javap - class file dis assembler
• ++
INTRODUCTION TO JAVA PROGRAMMING

17. JDK Kits and Editors
• J2SE Available on Sun Website
• Editors: Stick with javac, java & your
chosen editor (PFE, notepad, JCreator, …)
• Java Keywords: 48 reserved Keyword in
Java Language.
List can be checked at
http://java.sun.com/docs/books/jls/second_e
dition/html/lexical.doc.html
INTRODUCTION TO JAVA PROGRAMMING