Collection shouldn't be updated in lambda explanation Sometimes I see these kind of code. List<X> list = new ArrayList<>(); /*AnyCollection*/.forEach() .map(t -> list.add(t.getXXXX()));I think it's bad code. It's not thread safe If you use pa</x>…

Even it's any size or any type, system's behavior can be described by only "Input" and "Output'. Subroutines in program (function, method, ...) The behavior can be described by requested parameter and returned value. public String greet (S…