First Java Program - Tech Stack Journal

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 “App.java”
Open Command Prompt
Type cd d:\workspace to switch to the location of the file
Compile your program using javac -d App.java 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>javac App.java
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 App.java 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