Solving the "Which one should I use?" dilemma! 5 points for choosing between PHP interfaces, abstract classes, and traits

Once you become comfortable writing classes in PHP, the next things you encounter are "interfaces," "abstract classes," and ...
Ars Technica

Java - Can an interface define a class?

Obviously that doesn't compile, but I hate to make a file FooType.java with just the 5 lines above in it. Obviously that doesn't compile, but I hate to make a file ...
Ars Technica

interfaces and abstract classes, what am i doing wrong?

I would like MyCorpEmployees to have MyCorpEmployee overlords and underlings, and OtherEmployees to have OtherEmployee overlords and underlings. or, i did yesterday. i'm really thinking along the ...