#If you want to remove Openjdk only, execute the following command on terminal:
sudo apt-get remove openjdk*

#If you want to remove Openjdk along with dependencies, execute the following command on terminal:
sudo apt-get remove --auto-remove openjdk*

#If you want to remove Openjdk and it’s configuration files, execute the following command on terminal:
sudo apt-get purge openjdk*

#If you want to remove Openjdk along with dependencies and it’s configuration files, execute the following command on terminal:
sudo apt-get purge --auto-remove openjdk*
  
#don't forgive to give a thumbs up