Step-by-step – Oracle JDK 7 Ubuntu 21.04 Installation

Installing

2. 2. Downloading Oracle JDK 7

   Download Oracle Java SE 7 JDK for Linux.

   Oracle JDK i586/x8664 tar.gz

   Select Oracle JDK 7 for Linux

   If you are using Firefox then on Prompt Choose “Open with Archive Manager”:

   

   Or After try to Select the Package by the Downloads Button on Top Panel:

   

   Instead, on Google-Chrome simply try to Choose the Package on the Bottom Panel:

   

   How to Install Chrome Browser on Linux

3. 3. Extracting Oracle JDK 7

   Then Extract JDK 7 into /tmp
   Possibly Double-Click/Right-Click to Open with Archive Manager.
   Or from Shell:

   tar xvzf ~/Downloads/jdk-7*.tar.gz -C /tmp/

   

4. 4. Setting Up Oracle JDK 7

   Next Relocate Oracle JDK 7 Contents
   Login as the SuperUser:

   sudo su

   Authenticate with the User Admin Pass.
   If Got “User is Not in Sudoers file” then see: How to Enable sudo
   To Make a jvm Directory Only if Not already there
   (You can directly copy & paste the commands into the terminal)

   if [ ! -d "/usr/lib/jvm" ]; then mkdir /usr/lib/jvm; fi

   Set the root superUser as owner

   sudo chown -R root:root /tmp/jdk1.7*

   Then to shift the Oracle JDK 7 contents

   mv /tmp/jdk1.7* /usr/lib/jvm/
   

5. 5. Installing Oracle JDK 7

   Next to Install Oracle Java JDK 7.

   update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.7*/bin/java 1065
   

   update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.7*/bin/javac 1065
   

   update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/jdk1.7*/bin/jar 1065
   

   update-alternatives --install /usr/bin/javaws javaws /usr/lib/jvm/jdk1.7*/bin/javaws 1065
   

   Checking or Setting the System Java Version in Use
   with

   update-alternatives --config java

   And for the Java Compiler instead:

   sudo update-alternatives --config javac

   To Switch of Java Version Just Enter the Selection Number on First, Column. :)
   Last Achieve the SuperUser session:

   exit