On this post, I will guide you on installing Java on your development Linux machine. I decided to do this post after getting some questions on how do I manage multiple java versions in my Development environments if I use something to manage it like Sdkman, which I don't, in this post I will explain why.
Being in this industry for over 20 years I have developed software and scripts in many different languages like JavaScript, Pascal, Go, Python and others but I am mainly a passionate Java developer and I am committed to helping other colleagues to start programming in Java and help to demystify the fallacy that Java is complex or difficult to start. Java is the most used programming language for developing complex and enterprise software and it has by far the better ecosystem with it's available libraries, IDEs and tooling.
My preferred development environment is Linux so I'd rather use Linux alternatives to manage java SDK installations as it's built-in in Linux and allow you to manage not only java but any other binaries you want to manage and make accessible in your command line when using Linux. I will guide you to the process of installing Java 11 and running your first Hello World application using it.
The full installation process will be using the command line. So let's start, open a terminal console and cd
to your preferred working directory.
- Make sure to have wget installed.
sudo apt update && sudo apt install wget
- Download openjdk:
wget https://download.java.net/openjdk/jdk11/ri/openjdk-11+28_linux-x64_bin.tar.gz
Can check for updated java 11 versions here: https://jdk.java.net/java-se-ri/11
- Once download finished, add permissions:
chmod +x openjdk-11+28_linux-x64_bin.tar.gz
- Create folder where jdk will be installed
mkdir /usr/lib/jvm/open-jdk-11
- Extract it to /usr/lib/jvm/open-jdk-11 folder you have just created.
tar -xzf ./openjdk-11+28_linux-x64_bin.tar.gz -C /usr/lib/jvm/open-jdk-11 --strip-components=1
-
Update alternatives to add java, javac, jshell and jar
- list installed version
update-alternatives --list java
- configure java installation
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/open-jdk-11/bin/java 1
- configure javac installation
sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/open-jdk-11/bin/javac 1
- configure jar installation
sudo update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/open-jdk-11/bin/jar 1
- configure jshell installation
sudo update-alternatives --install /usr/bin/jshell jshell /usr/lib/jvm/open-jdk-11/bin/jshell 1
- Test installation, get java version:
java -version
- Test installation using jshell
jshell
- Type in
System.out.println("Hello World");
- Hit
Ctrl + D
to exit.
If you have multiple versions of java installed using this same process above, you can just switch between them using alternatives,
- Display installed versions of java
sudo update-alternatives --display java
- Config the version you want to use:
sudo update-alternatives --config java
Adding a new version and switching between them
Based on some comment suggestions I decided to extend the post to have a second version installed and show explicitly how to switch between them.
Lately I've been using Azul JVMs mostly so this time I will download the latest LTS Java 17 Open JDK from Azul
- Download it with curl, I am placing it in my $HOME/tmp file:
curl -L https://cdn.azul.com/zulu/bin/zulu17.32.13-ca-jdk17.0.2-linux_x64.tar.gz > ~/tmp/zulu17.32.13-ca-jdk17.0.2-linux_x64.tar.gz
Cd in the folder where you downloaded it.
- Create folder where jdk will be installed
sudo mkdir /usr/lib/jvm/azul-open-jdk-17
- Extract it to /usr/lib/jvm/azul-open-jdk-17 folder you have just created.
sudo tar -xzf ./zulu17.32.13-ca-jdk17.0.2-linux_x64.tar.gz -C /usr/lib/jvm/azul-open-jdk-17 --strip-components=1
- Check the config options for java
sudo update-alternatives --config java
You will see a list of configured java in alternatives, the new one is not there so we need to register it like we did in the beginning of this article, let's do it for java and javac, make sure to check the Selection number and add the new one to the next available, hit enter to continue with the current version before progressing, let's now register the new one we downloaded.
- configure java installation
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/azul-open-jdk-17/bin/java 2
The number in the end is the priority you can choose which one fits your goals better, by default the highest priority will be picked(lower number).
- Repeat for javac, check the installed javac with
sudo update-alternatives --config javac
and then configure it with next available Reference.
sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/azul-open-jdk-17/bin/javac 2
- configure jar installation
sudo update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/azul-open-jdk-17/bin/jar 2
- configure jshell installation
sudo update-alternatives --install /usr/bin/jshell jshell /usr/lib/jvm/azul-open-jdk-17/bin/jshell 2
Now that you have the new JDK installed and configured you can easily switch between versions using:
sudo update-alternatives --config java
Pick the number of the version you want from the Selection list.
Type in the Reference number for the one you want to be used from the displayed list and check with java -version
the same can be done for, javac, jshell, jar or any other tools you want to manage multiple versions using alternatives on linux.
You can now pick the option you want from the available list. That's it, you're done and have a working local development java environment ready to go.
If you want to quick start with creating an API in Java using Spring Boot, make sure you have git and maven installed(sudo apt install git && sudo apt install maven
) and check out this Spring Boot Crash Course, it's quite easy and quick to follow.
Top comments (14)
Hello thank for the article. How can I have multiple versions of JDK and Java ?
All the Linux distro have open-jdk in /etc/alternatives. Can I have jdk 11 and jdk 8 tohether?
Also I want to have the JDK 8 in /usr and a PATH variable java_home or java8 in system varibles, but I understand that the only way is to add variable in .bashrc.
Can you make it clear ?
Thank you in advance
I have added details on the article with JDK 17 and how to switch between versions using alternatives.
If you installed and configured an additional version in the guides, could have been super helpful because that's the whole point - "working with multiple versions of java", otherwise it's just another "How to install java in Linux - Tutorial"
Still forced to just work with /etc/environment | $PATH update
Hi, I followed your suggestion and added newest LTS 17 at the end of the post with instruction on how to switch between them. Hope it helps.
Cheers
How to configure open jdk 8 with this?
The process is the same, you just have to adjust the paths in your local computer.
This is amazing! Thank you Marcos for this post!
Just what I was looking for. Thanks for sharing!
I am glad it helped.
I have a problem. Using the 'echo $ PATH' command returns me a value but when reviewing the 'etc/environment' file you see another value. The same goes for the JAVA_HOME variable. Could you tell me what it is? Thanks for the support.
Hum.... most likely you have in one of these files under your $HOME folder: .bash_profile, .bashrc, .zshrc or similar a configuration setting the $JAVA_HOME specifically to an existing installation? If you have I would recommend you to remove the entry and source the file or restart / login again to see if it's gone. In most cases you don't really need a $JAVA_HOME hardcoded in your profiles(with some exceptions).
If you type only
env
in your terminal you should see all existent variables in your machine.It was good working!
Thanks a lot.
Great, helped me learn about alternatives in linux as well
I've just added more details. Check out here: github.com/logbasex/coding-notes/b...