Core Java
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Testing System.in and System.out with system-rules
Writing unit tests is an integral part of software development. One problem you have to solve when your class under…
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Java8 Lambdas: Sorting Performance Pitfall EXPLAINED
Written in collaboration with Peter Lawrey. A few days ago I raised a serious problem with the performance of sorting…
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Separating Integration Tests from Unit Tests Using Maven Failsafe & JUnit @Category
Why Unit Tests Should Run Separately From Integration Tests TDD at the Unit Testing level is fairly straight-forward, since classes in unit…
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How to Translate SQL GROUP BY and Aggregations to Java 8
I couldn’t resist. I have read this question by Hugo Prudente on Stack Overflow. And I knew there had to…
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Fork/Join Framework vs. Parallel Streams vs. ExecutorService: The Ultimate Fork/Join Benchmark
How does the Fork/Join framework act under different configurations? Just like the upcoming episode of Star Wars, there has been…
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Given When Then in Java
tl;dr you can use labels to clarify a given-when-then style of testing. What is given-when-then? given-when-then is a commonly used…
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Fine points of protection
In the article Some Sentences about Java I wrote that “Protected methods and fields can be used from classes in…
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The Decorator Pattern With Java 8
In a recent post I described how the decorator pattern saved my day. I gave a small code snippet which…
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Java 8 Functional Programming: Lazy Instantiation
Singletons often instantiate themselves lazily, and sometimes, if the object is heavy enough, class fields can be instantiated lazily. Generally,…
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