Setting Up JDK, PATH, and VS Code

Before you can write and run Java programs, you need a working development environment. This guide walks you through installing the JDK, configuring the PATH environment variable, and setting up Visual Studio Code as your Java editor.

Step 1: Install the JDK

The JDK (Java Development Kit) contains everything you need to compile and run Java code, including the compiler (javac) and the runtime (java).

Choose a Distribution

Java has several distributions built from the same OpenJDK source. Popular choices include:

• Eclipse Temurin (Adoptium) — free, widely used, and well-supported.
• Oracle JDK — official Oracle build.
• Amazon Corretto, Microsoft Build of OpenJDK, Azul Zulu — production-ready alternatives.

Pick a Long-Term Support (LTS) version such as Java 17 or Java 21 for stability.

Install It

Windows

1. Download the .msi installer from your chosen distribution.
2. Run the installer and follow the prompts.
3. Note the install location, typically C:\Program Files\Eclipse Adoptium\jdk-21....

macOS

1. Download the .pkg installer, or use Homebrew:

   brew install temurin
   

2. The JDK is installed under /Library/Java/JavaVirtualMachines/.

Linux

1. Use your package manager, for example on Ubuntu/Debian:

   sudo apt update
   sudo apt install temurin-21-jdk
   

2. Or download the .tar.gz, extract it, and place it in /opt/.

Step 2: Configure the PATH

The PATH environment variable tells your operating system where to find the java and javac commands so you can run them from any directory.

Set JAVA_HOME

JAVA_HOME points to your JDK installation folder. Many tools (Maven, Gradle, IDEs) rely on it.

Windows

1. Open Start → search Environment Variables → Edit the system environment variables.
2. Click Environment Variables.
3. Under System variables, click New:
   • Variable name: JAVA_HOME
   • Variable value: C:\Program Files\Eclipse Adoptium\jdk-21...
4. Find the Path variable, click Edit, then New, and add:

   %JAVA_HOME%\bin
   

5. Click OK on all dialogs.

macOS / Linux

Add the following to your shell profile (~/.zshrc, ~/.bashrc, or ~/.bash_profile):

export JAVA_HOME=/path/to/your/jdk
export PATH=$JAVA_HOME/bin:$PATH

Then reload the profile:

source ~/.zshrc

On macOS you can locate the JDK automatically:

export JAVA_HOME=$(/usr/libexec/java_home -v 21)

Verify the Installation

Open a new terminal or command prompt and run:

java -version
javac -version

You should see the version you installed. If the commands are not found, double-check the PATH entry and make sure you opened a new terminal so the changes take effect.

Step 3: Set Up VS Code

Visual Studio Code is a lightweight, free editor with excellent Java support through extensions.

Install VS Code

Download and install VS Code from the official website for your operating system.

Install the Java Extension Pack

1. Open VS Code.
2. Click the Extensions icon in the sidebar (or press Ctrl+Shift+X).
3. Search for Extension Pack for Java (published by Microsoft).
4. Click Install.

This pack bundles several essential extensions:

• Language Support for Java — code completion, navigation, and error checking.
• Debugger for Java — set breakpoints and step through code.
• Test Runner for Java — run and debug JUnit tests.
• Maven for Java and Gradle for Java — build tool integration.
• Project Manager for Java — manage projects and dependencies.

Point VS Code at Your JDK

VS Code usually detects JAVA_HOME automatically. To set it explicitly:

1. Open the Command Palette (Ctrl+Shift+P).
2. Search for Preferences: Open User Settings (JSON).
3. Add a java.jdt.ls.java.home entry pointing to your JDK:

   {
     "java.jdt.ls.java.home": "/path/to/your/jdk"
   }
   

Step 4: Write and Run Your First Program

1. Create a folder for your project and open it in VS Code.
2. Create a file named Hello.java:

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

3. Click the Run button above the main method, or open a terminal and run:

   javac Hello.java
   java Hello
   

You should see Hello, Java! printed to the console.

Troubleshooting

• java: command not found: The PATH is not set correctly, or you did not open a new terminal after editing it.
• Wrong Java version: Multiple JDKs may be installed. Check JAVA_HOME and the order of PATH entries.
• VS Code does not recognize Java: Reload the window (Ctrl+Shift+P → Developer: Reload Window) and confirm the Extension Pack for Java is installed and enabled.

With the JDK installed, the PATH configured, and VS Code ready to go, you now have a complete environment for learning and building Java applications.