In a continuation of my previous thread, I have found that a lot of my classes contain collections. Eg:

Engine - contains collection of pistons - piston - contains collection of xyz parts

Thus there is a hierarchy, as every component contains a collection of parts, which goes on and on.

This is a coding scenario I have not come across before. Constantly writing code like so:

```
class Part (Replace Part with apt name)
{
List<APart> parts ...
}

```

And then the same for APart, as that contains a collection of inner parts, is very tedious and therefore making me question whether this is the right way to code.

Is there a better way to write this sort of code? Anything like AOP etc I am open to (Though AOP is for cross-cutting concerns).