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Writing tests for asynchronous applications has never been much fun as we’re always struggling with the problem how to determine state changes, handle process terminations, dealing with timeouts or failures and stuff like this. Awaitility eases this process for us offering a nice DSL, rich support for languages like Scala or Groovy and an easy-to-use syntax that’s even more fun when using it with Java 8′s lambda expressions. In the following short introduction I’d like to demonstrate writing some tests different scenarios. ...

HipChat is Atlassian’s alternative to Slack and its solution to team collaboration chats. Atlassian Connect offers developer tools to bootstrap applications, connect to Atlassian’s cloud products with easy and in combination with HipChat’s REST APIs allows us to write integrations for such a chat server in no time. In the following tutorial I’d like to show how to write an integration within a few steps using Atlassian Connect, Node.js and Express and how to connect the integration to a HipChat server. ...

These days where a cheap GPU for about 100 € is capable to create 3 billion of MD5 Hashes per second, we need not only need to use salts the right way but we also need to choose a strong, non-reversible and slow hashing schemes when storing passwords in our application. Heimdall is a library that implements a secure and upgradable password hashing mechanism and uses at the time of writing this article PBKDF2 SHA-1 HMAC with 20000 iterations and a 192 bit (24 byte) salt per default. ...

Spring Boot allows us to create RESTful web-services with ease, Swagger specifies a format to describe the capabilities and operations of these services and with Swagger UI it is possible to explore our REST API with a nice graphical user interface in our browser. Springfox is a project that aims at creating automated JSON API documentation for API’s built with Spring and is used in the following tutorial to integrate Swagger into a sample application. ...

A variety of different tools exists to help us analyze RESTful web-services and create documentations for their APIs in different formats. In the following tutorial I’d like to demonstrate how to document an existing JAX-RS web-service in multiple formats like Swagger, AsciiDoc or Plain Text using Maven, the JAX-RS Analyzer and the JAX-RS Analyzer Maven Plugin. The JAX-RS Analyzer gathers its information not only by reflection like most other tools but also by bytecode analysis and therefore does not require us to add special annotations for documentation to our code. ...

Mutation testing makes an interesting addition to the classical test coverage metrics. They seed mutations (errors) into the code, run the project’s tests afterwards and if the tests fail, the mutation is killed – otherwise it lived and we have a possible indication of an issue with our tests. In the following short tutorial. I’d like to demonstrate how to setup mutation tests with the PIT/Pitest library and Maven and generate reports. ...

Nowadays in the realm of hybrid mobile application development there is a variety of available frameworks worth having a look at. In the following tutorial I’d like to demonstrate the development life-cycle for a complete mobile application using Ionic, Cordova and AngularJS (and others) covering every step from the initial project setup, creating Angular Controllers, Directives, adding Cordova Plug-Ins, running and testing the application in the browser and emulator up to finally running the application on an Android device and assembling files for a release. ...

Using immutable objects in Java (and other programming languages as well) is a good thing because immutable objects may be shared safely, are thread-safe and reduce the risk of side effects in your applications. Nowadays multiple frameworks exist to reduce the need of writing boilerplate code here but there is one special framework whose features I’d like to demonstrate in the following short tutorial. It hooks into your application using annotation processing and generates type-safe builders, toString, hashCode, equals methods for you, supports lazy attributes, singleton instances, serialization into data-formats like JSON and a lot of other features,too. ...

Sometimes when writing an application we might consider using an in-memory file system to speed up data access or to create some kind of cache. There are different libraries to help us here but one looks especially promising for me because it supports almost every functionality of the Java NIO File APIs added in Java 7 – from creating, reading, deleting files and directory to handling symbolic and hard links or watching directory changes with a WatchService. ...

For the most of us developers, generating Java source files is an occasionally happening task and we’re dealing with it e.g. when writing annotation processors, writing tools or interacting with meta-data files. JavaPoet is a nice library to simplify such tasks, offering an intuitive fluent-builder API to generate source files in no time. In the following tutorial I’d like to share a few examples by writing code generators with the help of this library. ...