DEV Community

nabbisen
nabbisen

Posted on • Originally published at scqr.net

Java 21 on Devuan 5 (Debian 12): Install manually

#java #openjdk #devuan #debian

Summary

Around Java, the general-purpose programming language, the next LTS (Long Term Support) version of OpenJDK, 21, was released last month, on 17 Sep. 2023 πŸŽ‰

On Debian 12 - bookworm repositories, the current version is 17 aka the previous LTS.

This post shows how to install 21 manually on Devuan 5 - Daedalus based on Debian 12.

Alternatively, JDK 21 "x64 Debian Package" Oracle offers is available.

In addition, Just in order to taste the latest, Oracle offers Java 21 PlayGround, too, which doesn't require local installation.

Moreover, one of the easiest ways is to use "OpenJDK" Docker Official Image and its "21-bookworm" tag.

Environment

  • OS: Devuan 5 Daedalus
    • based on Debian 12 bookworm
  • App Engine: OpenJDK 21

Tutorial

Get OpenJDK package

Visit: https://jdk.java.net/21/

You can get it there. I used the command line below:

$ curl -LO https://download.java.net/java/GA/jdk21/fd2272bbf8e04c3dbaee13770090416c/35/GPL/openjdk-21_linux-x64_bin.tar.gz
Enter fullscreen mode Exit fullscreen mode

You can verify the download by comparing the checksums between the server and the local. Use the command lines below, for example:

$ echo "$(curl -s https://download.java.net/java/GA/jdk21/fd2272bbf8e04c3dbaee13770090416c/35/GPL/openjdk-21_linux-x64_bin.tar.gz.sha256) openjdk-21_linux-x64_bin.tar.gz" | \
      sha256sum -c
openjdk-21_linux-x64_bin.tar.gz: OK
Enter fullscreen mode Exit fullscreen mode

It means it was confirmed that the server checksum was equal to the local one:

$ # checksum of the downloaded file
$ sha256sum openjdk-21_linux-x64_bin.tar.gz
a30c454a9bef8f46d5f1bf3122830014a8fbe7ac03b5f8729bc3add4b92a1d0a  openjdk-21_linux-x64_bin.tar.gz
Enter fullscreen mode Exit fullscreen mode

Place files

Extract it:

$ tar xzf openjdk-21_linux-x64_bin.tar.gz
Enter fullscreen mode Exit fullscreen mode

The result is as below:

$ ls {.,jdk-21}
.:
jdk-21  openjdk-21_linux-x64_bin.tar.gz

jdk-21:
bin  conf  include  jmods  legal  lib  release
Enter fullscreen mode Exit fullscreen mode

Now you have jdk-21 directory which contains bin etc. πŸ‘

Set environment variables

Prepare PATH and JAVA_HOME.

As to PATH:

$ # case bash
$ export PATH=$(readlink -f ./jdk-21/bin):$PATH
$ # case fish
$ #set -x PATH $(readlink -f ./jdk-21/bin/):$PATH
Enter fullscreen mode Exit fullscreen mode

As to JAVA_HOME:

$ # case bash
$ export JAVA_HOME=$(readlink -f .)
$ # case fish
$ #set -x JAVA_HOME $(readlink -f .)
Enter fullscreen mode Exit fullscreen mode

Ready πŸ™Œ

Conclusion

Now Java 21 is in your hands:

$ java --version
openjdk 21 2023-09-19
OpenJDK Runtime Environment (build 21+35-2513)
OpenJDK 64-Bit Server VM (build 21+35-2513, mixed mode, sharing)
Enter fullscreen mode Exit fullscreen mode

Let's do test run. Create a .java file:

$ nvim HelloWorld.java
Enter fullscreen mode Exit fullscreen mode

Write below in it:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, world.");
    }
}
Enter fullscreen mode Exit fullscreen mode

The way to execute it directly is as below:

$ java HelloWorld.java
Hello, world.
Enter fullscreen mode Exit fullscreen mode

Yay. Next, try to compile it manually and run it:

$ ls HelloWorld*
HelloWorld.java

$ javac HelloWorld.java
$ # .class file is generated

$ ls HelloWorld*
HelloWorld.class  HelloWorld.java

$ java HelloWorld
Hello, world.
Enter fullscreen mode Exit fullscreen mode

Hello, the latest Java on the latest Devuan ☺

Top comments (0)

Read next

dbillion profile image

Should I Still Learn Java in 2024?

Oludayo Adeoye -

saladlam profile image

Jakarta Persistence API (JPA) example application: Northwind sample database

Salad Lam -

khmarbaise profile image

Maven 4 - Part I - Easier Versions

Karl Heinz Marbaise -

vishalwaje profile image

🌟 Today's Java session was a perfect blend of theory and practice! πŸ’‘

Vishal -