From 21 Sep 2017 on we have OpenJDK 9 in the backports repository for Debain Stretch. Perform the following steps to install version 9 on your machine:
Prepare your system:
Version 9 of OpenJDK did not make it into the standard repositories for Debian Stretch but is available via backports repository. To be able to use it add the following lines to the end of your /etc/apt/sources.list file:
# stretch backports deb http://http.debian.net/debian stretch-backports main
Install OpenJDK 9
The installation of version 9 is then straight forward:
sudo apt-get update sudo apt-get install -t stretch-backports openjdk-9-jdk
Check your default Java version
Normally, OpenJDK version 9 should be your default Java version by now. Verify this by performing this simple check:
java -version
On my 64-bit system the output is:
openjdk version "9-Debian" OpenJDK Runtime Environment (build 9-Debian+0-9b181-4bpo91) OpenJDK 64-Bit Server VM (build 9-Debian+0-9b181-4bpo91, mixed mode)
Set the default java version manually
In case the previous step did not show version 9 as your default java version you can set it manually.
- To check which JDK-Versions are available on your system perform:
sudo update-java-alternatives --list
On my system (64-bit) the output is:
java-1.8.0-openjdk-amd64 1081 /usr/lib/jvm/java-1.8.0-openjdk-amd64 java-1.9.0-openjdk-amd64 1091 /usr/lib/jvm/java-1.9.0-openjdk-amd64
- To update your all relevant symlinks at once use:
sudo update-java-alternatives --set java-1.9.0-openjdk-amd64
(in a 32-bit environment use -i386 postfix instead of -amd64)
This article is a follow up to installing OpenJDK 8 on Debain Jessie
