Spring Reactor common mistakes

I recently gotten fond of Spring Reactor, reactive java library used by Spring 5.0. There is a lot of resources out there which describe it, so I’m not going to repeat the internet here. But in short it makes any asynchronous development a LOT easier and I dare to say its the first library which makes it almost trivial. There is a catch, learning curve is steep. And when I mean steep I mean it took me at least half a year (senior java dev) to wrap my head around it. Me and my colleagues made some stupid mistakes so here are 4 so far, will add more in the future.

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Google analytics report parsing in Java 8

Google has deprecated Google Analytics API v3 in favor of its new reporting API (V4). New API is quite universal and easy to use and its java library gets the job done well with one exception: mapping result to Java types. It returns everything in strings and you have to parse the Reports yourself and map the values to your object. I recently had to load quite a lot of daily statistics from google analytics so I wrote a simple class which does this dirty work for me.

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NullPointerException thrown from out of nowhere

Today I spent 30 minutes debugging a code which was throwing a null pointer exception. I never seen it before so I ruled out the obvious suspects and checked during several debugging runs what is and what actually is not null. It was not my code and it looked a bit shady, but everything seemed fine in debugger and more importantly, nothing seemed to be null.

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Corsica GR20 trip

I spent this year’s vacation in Corsica mountains walking the half of GR20 trail. See this page for more info about GR20. We hiked only the nothern half from Callenzana to Vizzavona.  I had to quit one day early as my shoes transformed into sandals and my big toe had a nail problem. Plus after 9 days in the mountains, I had enough of rocks and was really forward to have a nice meal, hot shower and sleep in decent bed. Photos inside the article.

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Instrumentation Testing with Dagger and Espresso

dagger_espressoOver the Christmas holidays Google has integrated the Espresso testing framework into its android built tools and bumped the version to 2.0. Old espresso maven repos went dead because of that which forced us to temporally move to Jake Wharton’s repo until we got the time to move. I was the fortunate one who had to make the switch. This post describes the pitfalls of the upgrade.

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