Find duplicate code with CPD

A copy/paste detector I’m sure that you know PMD, the famous static code analyzer. But have you ever tried CPD? Installation CPD belongs to PMD. You have to install PMD first. Command line usage I give you some examples here. minimum-tokens (minimum duplicate size) and files (source directory) are the only required options. Then you can specify the […]

Analyze application performance with CDI Interceptors

Using interceptors for analyzing performance issues Do you know statements in your code like this? Analyzing how long the execution of a method takes is a cross-cutting concern. Cross-cutting concerns like transactions, caching or measuring latencies are aspects of a program that cannot be cleanly decomposed from the rest of the system. So they result in either code duplication or significant dependencies […]

Test JSON with a few lines of code

JSONassert helps you writing JSON unit tests You have to write a unit test and JSON is involved. Usually this will end up in a lot of lines of code. You know the situation, I bet. Here JSONassert comes into play. It allows to write JSON unit tests with just a few lines of code. For example checking an […]

Are we doing microservices?

Recently, an admin asked me if we are doing microservices. I thought about it for a few moments. And what I said comes here as a checklist. It’s a really simple test with quick yes or no. Single Responsibility Principle Is your service small and focused on doing one thing well? Domain-Driven Design Is your service […]

Reading YAML configurations in Java

How can I use YAML for my Java application? YAML is human-readable and a cool datat interchange format. It’s lean appearance make it special e.g. for configuration files or when humans view or edit data structures. It’s well suited for hierachical data presentation and you can easily map common data structures. Jackson and SnakeYaml Here I […]

Initializing HashMaps in Java

How can I initialize a HashMap with some pre-defined entries? In this article I’ll show you how you create a HashMap with values. Java doesn’t provide a method like Array.asList(). For initializing a map you have to implement something like that: So this is the double brace initialization idom. I don’t like this way. It’s not very readable, it’s creates a […]

Stability Patterns: Use Timeouts

„A resilient system keeps processing transactions, even when there are transient impulses, persistent stresses, or component failure disrupting normal processing.“ This is Michael Nygards definition of stability. In his book „Release it!“ he describes design and architectures patterns, which stop cracks from propagating and preserve at least partial functionality instead of total crashes. So, what are […]