Step-by-step – OpenJDK 15 Ubuntu 18.04 Installation

Installing

2. 2. Enabling OpenJDK 15 PPA

   Add OpenJDK 15 PPA for Ubuntu GNU/Linux

   Enabling OpenJDK 15 Repo for Ubuntu

   OpenJDK 15 PPA for Ubuntu

3. 3. Installing OpenJDK 15

   Then to Install OpenJDK 15 in Ubuntu
   First, to look up all the available flavors play:

   sudo apt search openjdk-15

   So next for OpenJDK JDK 15 issue:

   sudo apt install openjdk-15-jdk

   Where for the Java Runtime instead:

   sudo apt install openjdk-15-jre

   Authenticate with the User Admin Pass.
   If Got “User is Not in Sudoers file” then see: How to Enable sudo
   Now to Check the current Java:

   java -version

   And in output you find it:

   

   Finally, to check for available Java releases:

   sudo apt search openjdk | grep jdk