My interviewer, who claims to have a Ruby and Java background, asserted that Ruby modules are interfaces, similar to those in Java. He seemed annoyed when I disagreed.

I explained that Ruby modules are used for grouping methods to be shared between classes, whereas Java interfaces are specifications of class behavior. Furthermore, Java's static typing allows interfaces to be used in method signatures. However, because Ruby is dynamically typed, you don't need to specify the type of a method's arguments, which is another reason Ruby modules differ from Java interfaces.

My interviewer appeared displeased by these points. Perhaps he intended to convey that modules serve as Ruby's interfaces in a more general or abstract sense. If so, he should have elaborated further on his reasoning. Instead, he remained silent after I presented my arguments.

If this interaction is indicative of LinkedIn's engineering culture, then I consider it a lucky escape.

HackerRank/LeetCode type question