First Java Program

First Java Program

In our first Java program, we are printing a “Hello World!!!” message.

Steps to run this Java code:

Here is the code to copy:

package com.techstackjournal;

public class App {
	public static void main(String[] args) {
		System.out.println("Hello World!!!");

Where to write this Java code?

  • Text Editor
  • Integrated Development Environment (IDE)

Though we can write the program in a Simple Text Editor, it is always better to use IDE, as it provides intellisense while to type code. Intellisense means, providing auto-complete options as type your program.

Writing Java Program in Text Editor

  • Copy above program to a text editor
  • Create a workspace folder like “D:\workspace”
  • Save the file with name “”
  • Open Command Prompt
  • Type cd d:\workspace to switch to the location of the file
  • Compile your program using javac -d command
  • A class file with name App.class will be generated inside “com/techstackjournal” folders.
  • To run this program type java com.techstackjournal.App
D:\workspace>java com.techstackjournal.App
Hello World!!!

Writing Java Program in IDE

Choosing the IDE
  • There are several IDEs available in the market
  • Most used IDEs are Eclipse, IntelliJ IDEA, NetBeans
  • NetBeans is free and opensource IDEs
  • IntelliJ IDEA comes in Community and Commercial versions
  • IntelliJ IDEA Community is free but only for pure Java related programming
  • IntelliJ IDEA Commercial version supports other advanced features to work on web projects
  • Eclipse is free and opensource
  • Eclipse also comes in various versions and for various programming languages
  • Throughout this course I’ll assume that you have downloaded Eclipse IDE for Enterprise Java Developers
  • Eclipse downloads can be executed directly without installation
Create your Java program in Eclipse IDE
  • Extract the eclipse zip file
  • Get into eclipse folder and double click eclipse.exe
  • Eclipse prompts for selecting workspace, give a relevant name here like JavaPracticeWorkspace
  • Select Menu, File >> New >> Project
  • Select, Java >> Java Project, click Next
  • Enter the project name, FirstJavaProject, click Finish
  • Click on Yes, to open associated perspective, that is Java
  • Expand the newly created project
  • Right click on src folder and select, New >> Class
  • Remove the value for Package
  • Enter “App” for Name
  • Select the checkbox for “public static void main(String[] args)”
  • Click on Finish button, you’ll see that partial code is written for you in file
  • Add the print statement inside main method, System.out.println("Hello World!!!");
  • Press Ctrl+S to save the file
  • Right click anywhere in the Java program and select, Run As >> Java Application
  • The output will be printed in the “Console” view, just below the Java Editor