By default, Ubuntu Server does not come with OpenJDK installed. OpenJDK must be installed manually from the repository.
However, sometimes even after running “sudo apt-get update”, the OpenJDK package is not found on the repository, even though it should be available for installation. The installation will fail with the following error:
user@computer:~/Java$ sudo apt-get install openjdk-8-jdk Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package openjdk-8-jdk
How to Fix “unable to locate package openjdk-8-jdk” Error
If such an error happened to your Ubuntu Server installation, do not worry! You do not need to rebuild the server installation from scratch; you can install OpenJDK from another repository such as the Debian Jessie repository.
The installation from another sanctioned repository, like the Debian one, will not break your existing installation and repository setup. In fact, OpenJDK 8 from the official Debian repository is 100 percent compatible with Ubuntu Server since Ubuntu Server is based on Debian. If you use Ubuntu 16.04, follow these steps to get started.
First, you need to install the Debian Archive keyring package by issuing the following command:
sudo apt-get install debian-keyring debian-archive-keyring
Then, issue the following command (you can replace nano with vim or other text editors you like)
sudo nano /etc/apt/sources.list.d/debian-jessie-backports.list
In the text file, enter the following string:
deb http://httpredir.debian.org/debian/ jessie-backports main
Then, save the text file and quit nano. Afterward, you need to create another text file using this command:
sudo nano /etc/apt/preferences.d/debian-jessie-backports
Paste this string into the new text file:
Package: * Pin: release o=Debian,a=jessie-backports Pin-Priority: -200
Afterward, save the text file and quit Nano. Enter the following command to upgrade the package database:
sudo apt-get update
And finally, issue the following command to install OpenJDK from the Debian Jessie repository:
sudo apt-get -t jessie-backports install openjdk-8-jdk
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