Scope functions in Kotlin are powerful tools that can make the code more concise but, like any powerful tool, can also ruin it if not used properly. This article covers the typical scope function issues and gotchas and offers mitigation practices. (The article is based on my 25 min Droidcon…

So what’s the problem with NullPointerException in Kotlin? Both Google and JetBrains promote Kotlin as safe & interoperable language, not necessarily emphasizing enough that it’s not intrinsically free from NPEs, in fact, if misused Kotlin code will throw as many KNPEs and similar exceptions. …

I decided to learn how to surf several months ago, I watched YouTube tutorials and have practiced weekly since then. Yet, I’m still pretty bad at that. …

For anything but Unit-tests. My team works on one application, it has decent (80-90%) code coverage and yet every month we have regressions detected during manual QA process, which slip through automated tests. Why is that? Well, because code coverage doesn’t warrant good tests. Test coverage information only helps with…

RxJava in the unit-tests can swallow the exception which would crash the real Android app. Here is how to fix the tests. Suppose we’re using RxJava in our Android app, and we cover it with unit-tests. Does it mean the same code that passes the test won’t crash the app…

Kotlin Data Classes are great; they’re concise, they’re null-safe. Gson is great as well; it’s a de-facto standard for JSON parsing on Android for a good reason. But! Data classes parsed via Gson guarantee neither null-safety nor even default values. Or do they? The Problem There is an excellent article describing an…

The simple strategy for dealing with exceptions. Exception handling is still a debatable topic nearly 60 years after the invention. Thirty years later Java pioneered the checked exceptions, another clever but often misused concept which drew a lot of criticism and was abandoned by followers like Scala and Kotlin. …

A lot was written about the TDD approach, in essence, it relies on one assumption — your tests are fast. If the tests are slow Red—Green—Refactor cycle is permanently stuck on the tests execution phase rather than on coding. That also assumes that you do know how to write tests…

Dagger is an excellent tool for dependency injection (DI). It does most of the job in compile time, making applications smaller and faster and dependency resolving safer. What’s not great is the documentation. Dagger is not a simple tool by any means. …