Visiting JavaLand 2019

Last week I have attended JavaLand 2019 which was a great experience for me. Lots of different people, interesting talks and great speakers! It was my first time there and I have to admit: not only the usual conference content was great, but also the location was really unique – it’s located in Phantasia Land, an amusement park in Cologne, Germany.

I gained a lot of new ideas and thoughts which I want to share with you here. This is not a super-detailed summary of each talk, so don’t expect a complete lecture. Instead, I want to give you an idea of some talks, so you can dig deeper if you think it’s interesting for you. The reason is quite simple: Doing something on your own will bring the best learning experience. (smile)

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Caching in AWS Lambda


Me presenting Caching in AWS Lambda

In every software application, there are usually two main reasons to cache data: a) to improve performance and b) to reduce costs. Caching in AWS Lambda is not different. Instead, the reasons for caching might be even more important in this context. This blog post explains why it could be necessary for you and shows how to implement different caching options. It’s based on a talk I gave at the AWS User Group Stuttgart meetup in December 2018. You can find the slides here and the code is provided in this GitHub repo.

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Use Jersey and Spring in AWS Lambda

AWS Lambda is actually made to be used by implementing small functions which can be started quickly. So your code artifact should be as small as possible for a fast startup time. However, in the Java world there are nice frameworks like Jersey and Spring which can help you writing code for an API a lot! Unfortunately these frameworks can take up to a few MB and blow up your artifact, but you might have your reasons to use them in AWS Lambda, e.g. because you’re migrating an existing project to AWS Lambda. So let’s see, how you can use Jersey and Spring together in AWS Lambda! The code can be found in my GitHub repository lambda-jersey-spring-example.

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Starter Projects For AWS Lambda Using NodeJS And Java

Today I want to show you three starter projects for AWS Lambda using CloudFormation and SAM – Serverless Application Model. I always like if I have some boilerplate code and can get started quickly without copying code or project structures from an existing (and mature) project. Therefore I thought it’s good to have them in one repository. You can find them on GitHub. The projects can be used for NodeJS and Java. Also one project contains both: usage of Java and NodeJS Lambdas in one CloudFormation template.

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Deploy a Multi-Module Maven Project to Heroku

Recently I was building a private hobby project where I wanted to use Heroku to deploy some Microservices and get some experience with it. Since I’m a Java enthusiast, I wanted to use a Multi-Module Maven project to also share some classes to the different microservices. So my mission was to deploy each submodule to a different Heroku app (I know this is completely against the nature of Microservices to code them all in the same language and have them in one big project like a Monolith – but I have my reasons). Getting started with Heroku was quite simple, because they have a very nice guide to setup and run your first app in the cloud. Unfortunately Heroku only supports one Procfile per project, therefore it’s not so easy to deploy multiple submodules to it. But there is way: You can use Config Variables. Let’s see step by step how to use this!

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How to test a web app with popups using Selenium

Some time ago I had to test a web app where a popup was triggered if the user hovers over a specific link. This is not as easy as testing if an element contains a specific text. But it’s possible using Selenium Actions. These class provides methods to perform some custom gestures on a page, like moving to an element. Here is an example how to do this: Continue reading