About Java Programming Language

Java was developed by Sun Microsystems as an object-oriented language that is used for general purpose bus: programs and interactive world wide web based internet program. Java is a simple, object-oriented, robust, secure, portable, high performance, architecturally neutral, interpreted, multitreated, and dynamic language. It is used to developed applications such as games, office suites, and other various applications. It was originally developed for consumer devices such as TV set, internet appliances, etc. Originally named OAK but was renamed Java.

3 Categories of Java:
1 - Java Standard Edition(J2SE) - for desktop applications
2 - Java Enterprise Edition - for small footprint devices such as personal digital assitants(pda)
3 - Java micro edition - for mobile devices



4 Types of Java Application:
1. Mini Applications - Applets, the first type are essentially mini applications that run inside a java enabled browser such as netscape navigator and internet explorer.
2. Applications - The second type is your typical GUI(graphical user interface) such as the windows notepad, applications which does not require a web browser to execute it.
3. Line Application - A common line application that can be run from ms dos command prompt or a UNIX shell prompt.
4. Libraries - It is not an application rather it is more a collection of classes that belong to one package.

Java Application Development Cycle:

• Edit - using a text editor or an Integrated Development Environment(IDE), Java source codes(.java files) are created and stored to a disk.
• Compile - using a java compiler, java source codes are compiled into bytecodes and serve to a disk.
• Load - a java bytecode are loaded onto memory or library that are used by the java application.
• Bytecode-verify - the Java Video Machine(JVM) varifies that the bytecode does not violate any restrictions and compiles with the java applications.
• Execute - the java application is then interpreted.

Sample java code:

public class first java program
{
               public static void main(String arg [ ] );
{
               System.out.println("My First Java Program");
}
}