Tech

Recently in a project I encountered the following problem: The development team used Git with a branch-per-feature-like workflow and the integration server, Bamboo in this case, was configured not only to run the integration-tests for the master-branch but also for every change in a feature branch. As the team developed a Java EE web application ports like 8080 occasionally were already bound and builds failed. I knew a plug-in for Jenkins CI I to search for available ports and assign them to a build variable but I wanted to control such information directly within the Maven build life-cycle so I searched and finally found Sonatype’s Port Allocator Plug-in for Maven. ...

Sometimes in a project there is the need to run tests for your client-side code, written in JavaScript from a Maven build. One reason might be that Maven manages a complex build life-cycle in your project and you need a close integration for your JavaScript tests, another one might be that you’re in an environment where it is complicated to install and manage additional software like an integration- or build-server. ...

Using the Java Persistence API and a decent persistence provider allows us to configure and fine-tune when and how the second level cache is used in our application. In the following short examples, we’re going to demonstrate those features written as JUnit test cases and running on a H2 in-memory database. Figure 1. Persistence Unit Configuration Setup First of all we need some basic setup to run the following examples .. we need to select a JPA persistence provider and database, create a persistence-unit configuration and an environment to run tests on an in-memory database. ...

Apache Avro is a serialization framework similar to Google’s Protocol Buffers or Apache Thrift and offering features like rich data structures, a compact binary format, simple integration with dynamic languages and more. In the following short five minute tutorial, we’re going to specify a schema to serialize books in a JSON format, we’re using the Avro Maven plugin to generate the stub classes and finally we’re serializing the data into a single file. ...

Querydsl is a framework that allows us to create elegant, type-safe queries for a variety of different data-sources like Java Persistence API (JPA) entities, Java Data Objects (JDO), mongoDB with Morphia, SQL, Hibernate Search up to Lucene. In the following tutorial we’re implementing example queries for different environments – Java Persistence API compared with a JPQL and a criteria API query, mongoDB with Morphia and last but not least for Lucene. ...

Parboiled is a modern. lightweight and easy to use library to parse expression grammars in Java or Scala and in my humble opinion it is perfect for use cases where you need something between regular expressions and a complex parser generator like ANTLR. In the following tutorial we’re going to create a simple grammar to specify a task list and write an implementation of a parser also as unit tests for each grammar rule in Java. ...

JAX-RS 2.0 aka JSR 339 not also specifies the API to build up a RESTful webservice but also enhances the client side API to ease up the process of writing a client for a REST service. In the following tutorial we’re building up a client for a ready-to-play REST service and explore the different new options e.g. how to handle requests in a synchronous or asynchronous way, how to add callback handlers for a request, how to specify invocation targets to build up requests for a later execution or how to filter the client-server communication using client request filters and client response filters. ...

Vert.x is a modern, lightweight framework to build high performance applications running on the Java Virtual Machine. The framework is polyglot so that you’re able to write your application in Java, Groovy, Ruby, Python or even JavaScript. In addition it offers a nice component system, an actor-like concurrency model a distributed event bus and an elegant API to create scalable applications in no time. In the following tutorial we’re going to build a websocket chat by creating a HTTP server and the websocket server using Vert.x, Java and Maven. ...

MongoDB is matured, document-oriented, cross-platform NoSQL database system with drivers available for a bunch of different programming languages. In the following short examples I’m going to write some integration tests for MongoDB using the MongoDB Java driver and the Flapdoodle library to create an embedded MongoDB instance for testing. We’re going to write tests for a simple persist-and-query scenarion and for a map-reduce function and in addition I’m going to show how to bind the start and stop of a MongoDB instance to a Maven goal using the embedmongo-maven-plugin. ...

Many articles have been written about JSR 335 aka Lambda Expressions for the JavaTM Programming Language but I like to try new things out for myself and that’s why I’d like to share my snippets here. Figure 1. Lambda Hacking using the NetBeans Developer Version Setup JDK and IDE It takes just some short steps to setup your environment … Download and install the Java 8 JDK with lambda support Download and install the NetBeans IDE Development version Configure NetBeans to use the Java 8 JDK (> Manage Platforms…) ...