Call a Remote Function Module (RFC) From SAP Cloud Platform ABAP Environment

First some important prerequisites (because I noticed these myself just late somewhere in the fine print after spending [wasting] some time trying things in my own trial accounts)

◉ You need a Global Enterprise Cloud Account – i.e. not just a trial account
◉ You need this for both, the SAP Cloud Foundry and the SAP Cloud Neo environment
◉ SAP Cloud Foundry and the SAP Cloud Neo need to be in the same region

Use SAP Cloud Connector + SAP Cloud Platform + Java to consume function in ABAP On-Premise system

Recently I was assigned to a prototype development which needs to consume some function modules in ABAP On-Premise system.

SAP Cloud for Customer is a cloud solution whose OData service / Web Service could directly be consumed by other application in the Internet. And the prototype I am working on recently needs to consume function modules in ABAP On-Premise system hosted in Corporate Network, which is not directly available for Internet application.