Looker supports OpenJDK version 11+ on customer-hosted Looker instances. This page describes how to upgrade from OpenJDK 8 to OpenJDK 11. Upgrading to OpenJDK 11 from OpenJDK 8 requires downloading and installing OpenJDK 11 and then downloading and installing a new looker startup script. For example:
- Stop the Looker process from shell, as the looker user: - sudo su - looker cd /home/looker/looker ./looker stop
- If you are updating a Looker cluster, repeat the previous step to stop Looker on every node. 
- Download and install OpenJDK 11. 
- Download the - looker11startup script.
- Delete the previous version of the - lookerstartup script from your- lookerdirectory:- rm looker
- Copy the - looker11startup script to your- lookerdirectory and rename the script- looker. The new startup script must be called- lookerto run properly:- mv <download_directory>/looker11 looker
- If you are updating a Looker cluster, repeat steps 3 through 6 on all nodes. 
- Start up Looker on all nodes. - ./looker start