ITEC 30 2

Introductory Overview

Instructors: Juel D. Coper, Rumer M. Bayot

Presentation Outline

1. Introduction
2. What is Java?
3. The Java Language Specification, API, JDK, and IDE
4. A Simple Java Program
5. Creating, Compiling and Executing A Java Program

Introduction

Computer Programs - Known as software.
- Defined as instructions to the computer, telling it what to do.
- Consists of a series of instructions directing the computer to perform specific operations.

Programming

Definition of Programming
- The process of creating a program that is executable by a computer, designed to perform required tasks.
Programming Language
- A formal language specifying a set of instructions to produce various kinds of output.
Characteristics of Programming Language
- Contains a specialized vocabulary allowing communication of instructions to a computer in an understandable way.

Types of Programming Languages

1. Machine Language

Definition: A computer's native language, which varies across different types of computers.
Description: A set of built-in primitive instructions specific to the hardware.

2. Assembly Language

Definition: Uses short descriptive words known as mnemonics to represent machine-language instructions.
Purpose: Developed to simplify programming relative to write in machine code.

3. High-Level Language

Platform Independence: Programs can be executed on various machines without modification.
Ease of Use: English-like syntax makes it easier to learn and implement.

Examples of High-Level Programming Languages

COBOL (COmmon Business Oriented Language)
FORTRAN (FORmula TRANslation)
BASIC (Beginner's All-purpose Symbolic Instruction Code)
Pascal
Ada (named for Ada Lovelace)
C
Visual Basic
Delphi
C++ (object-oriented, based on C)
C# (Java-like, developed by Microsoft)
Python
JAVA

What is JAVA?

Java Characteristics:
- High-Level Programming Language
- Platform Independent
- Object-Oriented
Definition:
- "Java is a powerful and versatile programming language for developing software running on mobile devices, desktop computers, and servers."

Advantages of Choosing JAVA

Simplicity: - Easier design, writing, and compilation compared to other languages.
Object-Oriented: - Supports modular programming and reusable code.
Platform Independence: - Flexible nature allowing cross-platform compatibility.
Distributed Environment: - Works effectively across distributed networks.
Security: - Java provides advanced security features.
Robustness: - Reliability and stability of applications.
Multithreaded Support: - Allows multiple threads of execution, enhancing efficiency.

About JAVA

Origin:
- Developed by a team led by James Gosling at Sun Microsystems, originally called Oak.
- Created in 1991 for embedded chips in consumer electronics.
- Renamed Java in 1995 for web application development.
Key Feature:
- Write Once, Run Anywhere (WORA): Code written in Java does not require recompilation to run on different platforms.

The Java Language Specification, API, JDK, and IDE

Java Language Specification: - A technical definition that encompasses syntax and semantics of Java.
Application Program Interface (API): - Contains predefined classes and interfaces for developing Java programs.
Java Development Kit (JDK): - A software development environment for Java applications and applets, includes:
- Java Compiler (javac)
- Java Archiving Tool (jar)
- Java Debugger (jdb)
- Java Runtime Environment (JRE) (for running Java programs)

Java Editions

Java Standard Edition (Java SE):
- Used to develop client-side applications that can run standalone or as applets from a web browser.
Java Enterprise Edition (Java EE):
- For developing server-side applications including Java servlets, JavaServer Pages (JSP), and JavaServer Faces (JSF).
Java Micro Edition (Java ME):
- Designed for mobile applications, such as those on cell phones.
JavaFX:
- A platform for creating rich internet applications using a lightweight user-interface API.

Java Versions

Major Java releases with corresponding dates:- JDK Alpha and Beta: 1995 - Basic features for application support.
- JDK 1.0: January 23, 1996 - Introduction of Access Specifies.
- J2SE 1.1: February 19, 1997 - Focus on Database connectivity & RMI.
- J2SE 1.2: December 8, 1998 - Introduction of JIT Compilation and Collection Framework.
- J2SE 1.3: May 8, 2000 - Introduction of JAR indexing, JAR sound.
- J2SE 1.4: February 6, 2002 - Introduced XML Processing, Printing, JDBC.
- J2SE 5.0: September 30, 2004 - Introduction of Boxing/Unboxing, Generics.
- Java SE 6: December 11, 2006 - Introduction of Pluggable Annotations, Java GSS.
- Java SE 7: July 28, 2011 - Introduction of Multiple Exception Handling and Automatic null Handling.
- Java SE 8: March 18, 2014 - Introduction of Lambda Expressions, Type Annotations.
- Java SE 9: September 2017.
- Java SE 10: March 2018.
- Java SE 11 (LTS): September 2018.
- Java SE 12 to SE 21: Released in ensuing years through March 2023.

Integrated Development Environment (IDE)

Definition: A software that provides a comprehensive environment for developing Java programs, including editing, compiling, building, debugging, and help features all integrated into a GUI.

Examples of IDEs

Netbeans
JCreator
JEdit
Eclipse
JBuilder
Blue J
JGRASP
Sun Java Studio

A Simple Java Program

Example Java Code

public class Welcome {
    public static void main(String[] args) {
        // Display message "Welcome to Java!" to the console
        System.out.println("Welcome to Java!");
    }
}

Structure of the Program

Class Declaration: public class Welcome
Main Method Declaration: public static void main(String[] args)
Commentary: Indicates the purpose
Print Statement: System.out.println("Welcome to Java!");

Creating, Compiling and Executing a Java Program

Create/Modify Source Code: - Source code developed by the programmer is saved as Welcome.java.

public class Welcome {
      public static void main(String[] args) {
          System.out.println("Welcome to Java!");
      }
  }

Compile Source Code:
- Compile using Java Compiler: javac Welcome.java.
- If compilation errors occur, they will be displayed.
- Compiled code is stored on disk as Welcome.class.
Run Bytecode:
- Execute using JVM: java Welcome.
- If runtime errors or incorrect results occur, they will be reported.
- Confirm output on console: Welcome to Java!.

Key Components

Java Virtual Machine (JVM): A virtual machine that runs Java bytecode, implemented in software.
Bytecode: Architecture-neutral similar to machine instructions, executable on any platform with JVM.
Java Runtime Environment: Provides libraries, tools, and the JVM for running Java applications.