How to Install Oracle JAVA 8 on Ubuntu 20.04 LTS

In this article, We are going to perform How to Download and Install Oracle JAVA 8 on Ubuntu 20.04 LTS Manually or any Cloud Instance like Amazon EC2, Azure VM, Google Compute Engine,etc. with preinstalled

Introduction

Java is a set of software and specifications developed at Sun Microsystems. There are two tyes of Java Platforms are JDK (Java Development Kit) and JRE (Java Runtime Environment). Both are helpful for deploying applications on servers and debugging, JVM monitoring,developing.

Prerequisites

  • Ubuntu Server 20.04 LTS
  • SSH access with sudo privileges
To check Ubuntu version:
uname -a
OR
cat /etc/os-release
Output:
NAME="Ubuntu"
VERSION="20.04 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal
Follow the below steps to Install Oracle Java 8 on Ubuntu  20.04 LTS Manually using command line.

Step #1: Download Oracle Java 8

Generally Oracle will not allow to download directly without accepting their licenses. We have to create one account in Oracle java website by your personal or official mail. After accepting license download the application from browser to local machine. This link takes you to the Oracle home website Oracel Java SRE. Once you opened above link goto “JAVA SE Development Kit 8u241” section, download “jdk-8u251-linux-x64.tar.gz” setup for Ubuntu click on “Accept License Agreement” Check Box. download oracle java 8 for ubuntu 20.04 LTS After downloading into local machine, using SCP/SFTP/FTP transfer the file from local machine to Ubuntu server.

Step #2: Copy downloaded Setup and Extract

Create a directory /opt/jdk
sudo mkdir  -p /opt/jdk
Copy the tar  file from the directory copied from local machine to server to /opt/jdk folder and execute below command:
sudo cp -rf /home/sivasai/jdk-8u251-linux-x64.tar.gz /opt/jdk/
cd /opt/jdk/
sudo tar -zxf jdk-8u251-linux-x64.tar.gz
Now unarchived the file and check the content by long-list:
ls

Step #3: Install Oracle Java 8 on Ubuntu 20.04 LTS with Alternatives

Use update-alternatives command to configure java on your system
sudo update-alternatives --install /usr/bin/java java /opt/jdk/jdk1.8.0_251/bin/java 100
After executing above command it shows below output:
Output:
update-alternatives: using /opt/jdk/jdk1.8.0_251/bin/java to provide /usr/bin/java (java) in auto mode
Note : Its not particularly o/p if you have installed open jdk before

Step #4: Verify Update Alternatives

Enter below command shows output:
sudo update-alternatives --display java
Output:
$ sudo update-alternatives --display java
java - auto mode
  link best version is /opt/jdk/jdk1.8.0_251/bin/java
  link currently points to /opt/jdk/jdk1.8.0_251/bin/java
  link java is /usr/bin/java
/opt/jdk/jdk1.8.0_251/bin/java - priority 100
To change for alternative mode if you already already any java version:
sudo update-alternatives --config java
It prompts for selecting by 0,1,2..so choose accordingly:
Output
There are 4 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                  Priority   Status

------------------------------------------------------------

  0            /usr/lib/jvm/java-13-oracle/bin/java   1091      auto mode

  1            /opt/jdk/jdk-12.0.2/bin/java           2         manual mode

* 2            /opt/jdk/jdk-13.0.2/bin/java           1         manual mode

  3            /opt/jdk/jdk1.8.0_251/bin/java         100       manual mode

  4            /usr/lib/jvm/java-13-oracle/bin/java   1091      manual mode

Press <enter> to keep the current choice[*], or type selection number: 3

update-alternatives: using /opt/jdk/jdk1.8.0_251/bin/java to provide /usr/bin/java (java) in manual mode

Step #5: Setting the JAVA_HOME and JRE_HOME Environment Variables

To define the enviroment variable:
sudo  nano /etc/environment
Paste the below variable on the file:
/etc/environment
JAVA_HOME=/opt/jdk/jdk1.8.0_251
JRE_HOME=/opt/jdk/jdk1.8.0_251/jre
To check variables defined:
source /etc/environment
echo $JAVA_HOME
Output:
/opt/jdk/jdk1.8.0_251
sudo apt-get update

Step #6: Verify Java Version

To check the java version:
java -version
Output:
java version "1.8.0_251"
Java(TM) SE Runtime Environment (build 1.8.0_251-b08)
Java HotSpot(TM) 64-Bit Server VM (build 25.251-b08, mixed mode)
If you seeing output like above then we have  successfully set up the Java 8 on Ubuntu.
OR if you are getting any issue to check java version then install below package
sudo apt-get install libc6-i386
Conclusion: In this article, We have covered download Oracle Java 8 from official site, install oracle java 8 on Ubuntu 20.04 LTS using command line, configured JAVA_HOME and JRE_HOME, verified installed version.
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20 thoughts on “How to Install Oracle JAVA 8 on Ubuntu 20.04 LTS”

  1. Helps but probably shouldn’t have specific of commands/ For home directory references use ~ instead and use a * on java version number, at least part of it…
    example: “sudo cp -rf ~/jdk-8u2*-linux-x64.tar.gz /opt/jdk/”

    Reply
  2. I get the following Error;
    sudo update-alternatives –install /usr/bin/java OracleJava /usr/lib/jvm/jre1.8.0_301/bin/java 1
    update-alternatives: error: alternative link /usr/bin/java is already managed by java

    What happened?

    Reply

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