Do you want to know how to develop your skillset to become a Java Rockstar?

Subscribe to our newsletter to start Rocking right now!

To get you started we give you our best selling eBooks for FREE!


1. JPA Mini Book

2. JVM Troubleshooting Guide

3. JUnit Tutorial for Unit Testing

4. Java Annotations Tutorial

5. Java Interview Questions


and many more ....



Test your Dependencies with Degraph


I wrote before about (anti)patterns in package dependencies. And of course the regular reader of my blog knows about Degraph, my private project to provide a visualization for package dependencies which can help a lot when you try to identify and fix such antipatterns. But instead of fixing a problem we all probably prefer preventing the problem in the first place. Therefore in the latest ...

Read More »

Replica Set Members in Mongodb


In the previous articles we have discussed many aspects of replica set in mongodb. And in those articles we have talked many things about members. So, what are these members? What is their purpose? Let us discuss about these things in this article. What are members in mongodb? In short terms the members in mongodb are the mongod processes which ...

Read More »

Hibernate hidden gem: the pooled-lo optimizer


Introduction In this post we’ll uncover a sequence identifier generator combining identifier assignment efficiency and interoperability with other external systems (concurrently accessing the underlying database system). Traditionally there have been two sequence identifier strategies to choose from.         The sequence identifier, always hitting the database for every new value assignment. Even with database sequence preallocation we have ...

Read More »

A JUnit Rule to Run a Test in Its Own Thread


Occasionally it would be helpful to be able to run a JUnit test in a separate thread. In particular when writing integration tests that interact with encapsulated ThreadLocals or the like this could come in handy. A separate thread would implicitly ensure that the thread related reference of the threadlocal is uninitialized for each test run. This post introduces a ...

Read More »

Drools Executable Model


The Executable Model is a re-design of the Drools lowest level model handled by the engine. In the current series (up to 6.x) the executable model has grown organically over the last 8 years, and was never really intended to be targeted by end users. Those wishing to programmatically write rules were advised to do it via code generation and ...

Read More »

Template Method Pattern Example Using Java Generics


If you find that a lot of your routines are exactly the same except for certain sections, you might want to consider the Template Method to eliminate error-prone code duplication. Here’s an example: Below are two classes that do similar things:                 Instantiate and initialize a Reader to read from a CSV file. Read ...

Read More »

Camel on JBoss EAP with Custom Modules


Apache Camel — the best open source integration library Apache Camel is an awesome, open-source, integration library that can be used as the backbone of an ESB, or in stand alone applications to do routing, transformation, or mediation of systems (read: integrating multiple systems). Camel is quite versatile and does not force users to deploy into any particular container or ...

Read More »

Grouping, sampling and batching – custom collectors in Java 8


Continuing first article, this time we will write some more useful custom collectors: for grouping by given criteria, sampling input, batching and sliding over with fixed size window. Grouping (counting occurrences, histogram) Imagine you have a collection of some items and you want to calculate how many times each item (with respect toequals()) appears in this collection. This can be achieved ...

Read More »

Use Cases for Elasticsearch: Flexible Query Cache


In the previous two posts on use cases for Elasticsearch we have seen that Elasticsearch can be used to store even large amounts of documents and that we can access those using the full text features of Lucene via the Query DSL. In this shorter post we will put both of use cases together to see how read heavy applications ...

Read More »
Want to take your Java Skills to the next level?
Grab our programming books for FREE!
  • Save time by leveraging our field-tested solutions to common problems.
  • The books cover a wide range of topics, from JPA and JUnit, to JMeter and Android.
  • Each book comes as a standalone guide (with source code provided), so that you use it as reference.
Last Step ...

Where should we send the free eBooks?

Good Work!
To download the books, please verify your email address by following the instructions found on the email we just sent you.