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Calculate memory usage of Java objects

With Twitter’s ObjectSizeCalculator If you are looking for an easy way to estimate the object size than this could interest you. The memory size of your object depends on the architecture, the actual vm implementation and whether the VM is 32 or 64-bit. ObjectSizeCalculator supports only the Hotspot JVM. For more information see the javadoc ObjectSizeCalculator. […]

Hey SDKMAN!

This tool is great! I came across SDKMAN in a Spring tutorial. It’s a tool like rvm which helps you to manage parallel version of a SDK for the JVM like: * Java * Gradle * Groovy * Kotlin * Maven * Scala * Spring Boot * Vert.x It’s what compelling, so I installed it […]

Embedded Jetty with Servlet and Annotations

How do I programmatically configure Jetty that I can use Servlet Annotations? If you doing just servlets with jetty, this article could be interesting for you. I show you how I did it. Here comes the configuration: And I defined the following dependencies in build.gradle. That’s all. Hope this helps! Here is the link to […]

Why you should use new language features

A quick list I put together a list with a number of reasons why you should use new language features. The list includes points which are obvious, I learned or I found on the internet. improved design * easier to understand * easier to change * less defects effectiveness * using standards * getting help […]

Every push a build with Travis CI

Build and test your software projects automatically I wanted that cool build passed badge for my projects as I have seen at Github. So I had a look at Travis CI, which is a continuous integration service used to build and test software projects. Let’s have a look at the build file. .travis.yml That’s it. […]

Unit Testing Servlets with Mockito

A quick example how to write unit tests for servlets Okay, I’m writing a Servlet. So I want to write a unit test too. With Mockito this is a quite simple task. Here I show you a simple unit test for a Hello World Servlet. The Servlet returns only „Hello World“. Mockito offers various annotations. For […]

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 […]

Why are engineering values important?

Everything else will grow from values and behaviour Wikipedia writes „… Values can be defined as broad preferences concerning appropriate courses of action or outcomes. As such, values reflect a person’s sense of right and wrong or what „ought“ to be… Values tend to influence attitudes and behavior [value].“ And culture comes from these shared […]

How to specify Java Source and Target Compatibility in a Gradle multi project

I have a multiple project setup and I want to build top level projects using different JDKs. I did some experiments by myself and the following configuration worked for me (using gradle 3.1 and the wrapper function). At the root level my gradle.properties file looks like this: Default JDK should be JDK 7. So I defined this in […]

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 […]