Oracle Java Cloud Service is a part of the platform service offerings in Oracle Cloud. Powered by Oracle WebLogic Server, it provides a platform on top of Oracle's enterprise-grade cloud infrastructure for developing and deploying new or existing Java EE applications.
When getting started you will find a nice article: Creating an Oracle Java Cloud Service Instance by Using a QuickStart Template but that requires a specific subscription type: You must have a Universal Credits subscription in order to use QuickStart. This feature is not available to other subscription types.
For that reason, proceed with the Creating a Custom Oracle Java Cloud Service Instance and all prerequisites. The final setup would have:
Unfortunately, the provisioning process is not intuitive and brings some complexities from on-premises setup that could and should be eliminated on the Cloud platform.
Re-evaluate at a later time.