The guide walks through installing the newest LTS OpenJDK 17 on Ubuntu 22.04 and 20.04 with just a handful of commands and no unnecessary fuss. It explains why modern language features like sealed classes and pattern matching motivate moving from older JDKs such as Java 11, which many build tools still default to. The steps include updating the system, checking for existing Java installations, adding the appropriate PPA on Ubuntu 20.04, installing openjdk-17-jdk, and configuring alternatives so that java 17 becomes the default runtime. Finally, it shows how to verify the install, set JAVA_HOME for Maven, and update IDE SDK settings to avoid lingering references to older JDKs.

Installing OpenJDK 17 on Ubuntu 22.04 and 20.04

OpenJDK 17 is the newest LTS Java release that’s already making its way into production workloads. If you’re running Ubuntu 20.04 or 22.04 and need a clean install, this short guide will get you up and running—no fuss, no mysterious errors.

Why OpenJDK 17 Matters for Your Projects

You might wonder why anyone would bother switching to the latest JDK. I’ve seen developers stuck on Java 11 because their build tools refuse to compile code that uses new language features like sealed classes or pattern matching. Switching to OpenJDK 17 unlocks those goodies without dragging in a full Oracle JRE.

Prerequisites Before You Start

1. Update the system

   sudo apt update && sudo apt upgrade -y

Keeping packages current prevents version conflicts that could bite you later.

2. Check if another Java is already installed

   java --version

If a different JDK shows up, decide whether to keep it or remove it—mixing runtimes can trip your IDE into pointing at the wrong compiler.

Installing From Ubuntu Repositories (Easiest Path)

Ubuntu 22.04 ships OpenJDK 17 in its default repos, while Ubuntu 20.04 requires a small tweak:

• For Ubuntu 22.04

  sudo apt install openjdk-17-jdk

• For Ubuntu 20.04

The official repo contains only JDK 11 by default. Add the “jdk‑17” PPA:

  sudo add-apt-repository ppa:openjdk-r/ppa
  sudo apt update
  sudo apt install openjdk-17-jdk

The PPA step is necessary because Ubuntu 20.04’s base repos lag behind in JDK versions; the PPA keeps you on lockstep with the upstream OpenJDK releases.

Setting Java 17 as the Default Runtime

After installation, make sure the system picks the right one:

sudo update-alternatives --config java

Select the number that points to /usr/lib/jvm/java-17-openjdk-amd64/bin/java. This step is crucial if you have multiple Java versions; otherwise your shell could still be calling Java 11 silently.

Verifying Your Install

java --version
# should output something like:
# openjdk version "17.0.8" 2023-07-18 LTS

If that matches, congratulations—your environment is ready for modern Java projects.

Troubleshooting Common Issues

• “command not found” after sudo apt install – Double‑check that the package name was typed correctly. Ubuntu’s naming convention uses hyphens: openjdk-17-jdk.

• Maven complains about unsupported Java version – Ensure you’re running Maven with the same JDK by setting JAVA_HOME:

  export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64

Add that line to your .bashrc if it works.

• IDE still points to Java 11 – In Eclipse or IntelliJ, go to the project’s SDK settings and switch to the newly installed JDK. IDEs often cache the last used runtime.

That’s all there is to it: a couple of commands and a few sanity checks. If you hit any snags, feel free to ping the community; I’ve seen people stuck on subtle PATH issues that are easy to solve once spotted.