Programming to an interface

Program to an interface, not an implementation. This short sentence, introduced in 1994 by the GoF, is one of the most important design principles in software development. However, I have seen several projects where this principle has gone wrong. Here’s why: Interface vs. Interface If you come from a Java background like myself and you […]

Expression based security with Spring Security

Many web apps have a very simple security concept based on user roles. You might have some admin, some common users and maybe some more roles like a moderator or a super-user. Such a role concept can be easily implemented with Spring Security. For example, you could secure your app based on routes which are […]

Inject mocks with Spring’s @ContextConfiguration

One of the biggest strengths of Spring is its ability to make your code testable. By using dependency injection and inversion of control, the Spring context defines which objects will be wired into your beans. This makes it easy to wire services, repositories or what ever you like. But how to wire mocks in your […]

A mocked Spring security configuration for testing

Spring security is great! It gives you the possibility to secure your app and to create a login with a few simple lines of code. However, it could also become annoying during development, when you have to log yourself in again and again. So why not create a mocked Spring authentication for development and testing? […]

Gradle’s bootRun and Window’s command length limit

Sometimes Gradle’s bootRun and Window’s command length limit are two opponents. If you use bootRun to start your Spring Boot app from Gradle all class path dependencies will be added to the start command. Gradle will run something like this in the end:

1	java -jar MyApp.jar -classpath xx.jar,yy.jar,zz.jar,...

That’s fine and will work for a really long time. But […]

Create random test objects with Java reflection

Although Java is an object oriented language, you will often separate our data and your actual business logic. You will write POJOs, entities, domain models and DTOs which you will pass to services, repositories and controllers. If you do so, you will properly need test data for those objects. Often, the data you pass will […]

Using Spring Data for database views without an ID

A database view is a great way to prepare complicated data structures right in the database and present it in a more convenient way. We usually use database views to map our technical driven database structure (with a lot of tables and foreign keys) to a more business driven structure. This means that we might […]

Everytime a mock returns a mock a fairy dies

As I was reading about some Mockito features last week, I stumbled over the following tweet, which really made me laugh: Everytime a mock returns a mock a fairy dies — Damian Guy (@damianguy) 18. Oktober 2009 I actually found the reference to the tweet in the Mockito source code about “deep mocking” and it’s […]

When modularity comes down to OSGi

Last week I attended a tech talk by Christian Schlichtherle, organized by Euro Staff in Berlin. The talk was about modularity and its different forms in software development. Christian talked about packages, libraries, APIs, dependency management and – as always when it comes down to modularity – about OSGi. Every time somebody is talking about […]

Why using Spring’s @Value annotation is bad

@Value Configuration is an important topic of every application which has more than a couple of hundred lines of code. In case you are using Spring, you would typically use Spring’s @Value annotation to load values from a Java properties file. This could look like this:

@Service

public class MyService {

@Value("${my.config.property.key}")

private String someConfigValue;

//...

}

If you do so, Spring would inject the […]