I am the trainer of one standard course “Programming Language Concept” within SAP and there is a set of concept Covariance and Contravariance, which has only built-in support by a subset of programming language like Java. For those ABAPers who don’t have chance to touch this concept in their daily work, I have built a small example to simulate how the concept works in ABAP as well for ease of understanding. The example explained in this example is just a prototype purely for training and education purpose.I am the trainer of one standard course