Learning Java : First step - the Basics

Introduction

First I am going to start with few links that explains about the the basics of Java programming.

I learned java and object-oriented learning only from the Sun tutorial and hence planning to start the introductory section from there.

Things to do:

1. Install and run "hello world" application. The first step in learning any programming language is to run a "hello world" program. The link below provide more about it. Please go through all the section (takes ~10 to 15 minutes)
• Getting started link
2. Learn about object oriented programming concept from the following link (10 to 15 minutes)
• OOPs concepts

Reference - Sun Java main tutorial link:

• Sun Java Tutorial home page

If you finished the above steps then, you should have run the first java application from command-line DOS shell. In summary, you would have learned how a simple java program looks like, concepts of compiling and running java application.

Next I will explain how the same application can be run from an IDE (Integrated Development Environment).

Problems faced

•  In Windows machine, I could not find the 'javac' binary program to compile the code
• JDK should be downloaded and installed if we have to use Java for compiler
• What are JRE, JDK, JEE and other acronymns?
• JRE - Java Runtime Environment - For desktop stand-alone applications,  contains only files required to run java applications.
• JDK -  Java Standard Edition Development kit - For desktop applications, contains all the binary files to compile and run java applications. JRE is the subset of JDK
• JEE - Java Enterprise Edition - For web applications and enterprise level applications. JRE is the subset of JEE.
• When I run 'javac HelloWorldApp.java' in Command-line, I am getting '''javac' is not recognized as an internal or external command, operable program or batch file.'" error message?
• The PATH variable is not set correctly. 
• Solution 1 : Setup the windows PATH variable.
• Solution 2 : user the full path to compile the code 
• "C:\Program Files\Java\jdk1.6.0_17\bin\javac" HelloWorldApp.java

• HelloWorldApp.java

class HelloWorldApp {
   public static void main(String[] args) {
       System.out.println("Hello World!"); // Display the string.
   }
}