As for ArraySeq?, just use built-in arrays. I seem to remember I've answered this question before...
I assume that Seq and SeqView? are deprecated too. Can't remember what Seq is, but SeqView? is probably a read-only 'view' of a a sequence. Simply put, it exists because D and Java doesn't have 'const'. IIRC, there's also a PathView? in the FilePath? module.
With Seq and SeqView?. I wanted to know how to use them, I'm new at using interfaces and abstract classes, and I haven't done much inheritance. Abstract class's should be marked so, or are they all deprecated any way?
I don't know about D not having 'const'. For example you can put:
const NUM_OF_DOTS=1_000;
I'm actually doing Java at University, I'd have to say I'm struggling at the moment. And I don't know how to use Java's API much.