Unable to install Jenkins due to java package can not be installed

Hi,

When I tried to install Java package that is required for Jenkins install I see the following error and there is no clue how to get unblocked from this error. OS on the droplet is Ubuntu 18.04.

$ sudo apt install default-jre
Reading package lists... Done
Building dependency tree       
Reading state information... Done
**E: Unable to locate package default-jre**
 
$ java --version

Command 'java' not found, but can be installed with:

sudo apt install openjdk-11-jre-headless  # version 11.0.7+10-2ubuntu2~19.10, or
sudo apt install default-jre              # version 2:1.11-72
sudo apt install openjdk-13-jre-headless  # version 13+33-1
sudo apt install openjdk-14-jre-headless  # version 14~18-1
sudo apt install openjdk-8-jre-headless   # version 8u252-b09-1~19.10

$ sudo apt install openjdk-11-jre-headless
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package openjdk-11-jre-headless
$ 
$ sudo apt install   openjdk-14-jre-headless
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package openjdk-14-jre-headless
$ 
$ sudo apt openjdk-8-jre-headless
E: Invalid operation openjdk-8-jre-headless
$