flatMap() vs. concatMap() vs. concatMapEager() – RxJava FAQ

java-interview-questions-answers

There are three, seamlessly similar operators in RxJava 2.x: flatMap(), concatMap() and concatMapEager(). All of them accept the same argument – a function from original stream’s individual item to a (sub-)stream of arbitrary type. In other words if you have a Flowable<T> you provide a function from T to Flowable<R> for arbitrary R type. After applying any of these operators you end up with Flowable<R>. So how are they different? Sample project First ...

Read More »

Eclipse Projects: Level Playing Field

For many open source organisations, open means the same thing as transparent: open as in open book. At the Eclipse Foundation, we regard being transparent as the practice of making sure that the community can see and understand what the project is doing; and being open as the act of giving up absolute control and welcoming the community to participate ...

Read More »

You’re Doing It Wrong: Deadlines

We know that deadlines drive behavior. That’s why in scrum, and other agile methodologies, we timebox the development with those deadlines. They tell us: Focus on the important stuff, and make sure it’s done properly. Since they are good in essence, let’s see how we muck them up. Here’s the process. We prepare for the sprint, splitting stories, asking for ...

Read More »

Eager subscription – RxJava FAQ

java-interview-questions-answers

While teaching and mentoring RxJava, as well as after authoring a book, I noticed some areas are especially problematic. I decided to publish a bunch of short tips that address most common pitfalls. This is the first part. Observables and Flowables are lazy by nature. This means no matter how heavy or long-running logic you place inside your Flowable, it will get evaluated ...

Read More »

How to Manage a Manager?

No secret, we you all have managers. Some of them are great, while many are simply idiots. What do you do if you happen to have a boss that fits perfectly into this dominating category? Quit and try to find a better place? This may sound like good advice, but you know as well as I do that a new boss most ...

Read More »

3 Often-Overlooked Key APM Features

Core APM features aren’t going to be enough anymore. Market-leading apps are going above and beyond, setting new standards that others have to match. Every time any web app, whether it’s aimed at consumers or the enterprise, hits a new performance peak, that sets the baseline for user expectations. It may not be fair or reasonable, but that’s how the ...

Read More »

Kotlintest and property based testing

I was very happy to see that Kotlintest, a port of the excellent scalatest in Kotlin, supports property based testing. I was introduced to property based testing through the excellent “Functional programming in Scala” book. The idea behind property based testing is simple – the behavior of a program is described as a property and the testing framework generates random data to validate the ...

Read More »

Distributed Logging Architecture for Microservices

In this article we will see what are the best practices we need to follow while logging micro services and the architecture to handle distributed logging in micro services world. As we all know micro services runs on multiple hosts. To fulfill a single business requirement, we might need to talk to multiple services running on different machines. So, the ...

Read More »