An object-relational mapping implementation would need to systematically and predictably choose which tables to use and generate the necessary SQL. According to XP and TDD pioneer Ward Cunningham, “Test-first coding is not a testing technique”. In relation to this, design patterns encapsulate common, accepted, and proven ways of using language features together. Obviously, the deeper the inheritance hierarchy is, the greater the probability is that it gets complicated and hard to predict its behaviour. Therefore service-oriented applications are the successor to the multi-tier applications of the past ten years.

Logic variables pioneered by concurrent logic and concurrent constraint programming are powerful mechanisms for automatically synchronizing concurrent computations. Different user populations have different requirements and expectations when it comes to privacy; thus finding universally acceptable solutions is far from trivial.

The role of variables as elements for unspecified structures is very different from the roles of variables as formal parameters or updatable positions in functional and imperative languages. I can see how dependency injection is useful when you have different teams working on something you depend on when you'd have to have a delayed implementation decision, but this can be achieved though a regular factory as well. Moreover, there are languages where objects may have internally concurrent threads that are not freely created by message reception.