Install JDK and Tooling

Why this step matters

Before writing Java code, your environment must be correct and reproducible. A clean setup avoids hidden issues between local, staging, and production environments.

Install JDK 21+

Use an LTS distribution (Temurin, Oracle JDK, Corretto, or Zulu). Verify installation:

java -version
javac -version

Expected output should show version 21 (or newer).

JDK download links

Set `JAVA_HOME` and `PATH`

Make sure both are configured system-wide so terminal, IDE, Maven, and Gradle all use the same JDK.

macOS (zsh)

# ~/.zshrc
export JAVA_HOME=$(/usr/libexec/java_home -v 21)
export PATH="$JAVA_HOME/bin:$PATH"

Apply changes:

source ~/.zshrc

Linux

# ~/.bashrc or ~/.zshrc
export JAVA_HOME=/path/to/jdk-21
export PATH="$JAVA_HOME/bin:$PATH"

Windows (PowerShell)

Set environment variables in System Settings:

JAVA_HOME=C:\Program Files\Java\jdk-21
Add %JAVA_HOME%\bin to Path

Then reopen your terminal and check:

java -version

Use IntelliJ or VS Code

Choose one IDE and configure it properly.

Recommendation

For Java projects, I recommend using IntelliJ IDEA over VS Code for a more complete and reliable developer experience.

IntelliJ IDEA

Download: IntelliJ IDEA
Set project SDK to JDK 21+
Enable auto-import for Maven/Gradle
Install Java and Spring plugins if needed

IntelliJ Setup Video

VS Code

Download: Visual Studio Code
Install Extension Pack for Java
Install Language Support for Java(TM) by Red Hat
Set default Java runtime to your JDK 21+

Quick validation checklist

java -version and javac -version return 21+
JAVA_HOME points to your intended JDK
IDE project SDK uses the same JDK
A simple HelloWorld compiles and runs

With this baseline, you are ready for the next Java roadmap steps.