Posts about Java programming, Java news and comments!

  • HTTP Client ( Java 11 API - the practical example

    Java logo in binary code

    Any HTTP Client library in Java is a hell to me. Comparing to other technologies like Groovy which have built-in APIs, Java sucks. Projects use Apache HttpClient API for trivial tasks like testing, which I consider as a brain rape because of the usage difficulties. When the HTTP client was introduced and incubated in Java 9 I was like:

    Finally, we have our HTTP client, at least for testing!.

    Now it’s officially moved to package. I had to try it on my own in the home laboratory.

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  • Testing Java code performance with JMH

    JMH on code background

    Recently, I wrote a blog post about performance of Java Data classes. Many people pointed me out I did not write a JMH test. Instead, I wrote simple microbenchmark on my own, based on the Java performance book. Because it is, apparently, unreliable I had to write JMH test as well and compare results - trying to explain why it’s different. Let’s answer outstanding questions.

    What do you think? Am I, in fact, totally wrong here?

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  • Bug się rodzi - the most common Java bugs

    Santa with laptop

    Hello, fellow programmers! First of all, I wish you all Merry Christmas! Spend this time well, there is not many moments for rebuilding family bounds these days. This is the special, Christmas blog post. I named it that because it’s fun comparison with one of the most known Polish carols (listen it here, play it now) - “Bóg się rodzi”. The name is “God Is Born”. Polish word for God - “Bóg” - reads as same as “Bug”. How programming-ready this language is!

    Today, we are going to discover the most common Java bugs I have seen in my Java journey. Hope you won’t find them under the Christmas Tree :D (that’s another polish tradition - we are putting presents under the tree).

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  • Data classes in Java - runtime underperformance vs code readability

    Screen with some code

    BTW: Funny thing. Let’s go back to the day I started writing this blog. I thought I would never find enough topics to blog weekly. Now, the number is amazing. Optimistically, I should write about all of them in 2090. I am just saying - regardless to many people’s opinion, the blog exists.

    I recently wrote a constructor:

    Cuboid(double width, double height, double depth, byte r, byte g, byte b)

    It doesn’t look right. There are many values of the same (and similar, like bytes-doubles) type. On the other hand, what can be wrong with many parameters? I started to instantiate these cuboids. The order of parameters was obvious but I had to check it few times - it’s very painful. And, yet, I wrote it myself! What if someone else will try to use it?

    But hey, I can create additional data classes, right? So, I created two POJOs (Dimension and Colour) and changed the constructor to:

    Cuboid(Dimension dimension, Colour colour)

    Parameters now are related to the purposes they serve: dimension and colour. During the code review I received an honest but scary feedback though:

    Classic Daw. Are you mad? This is really inefficient way, you are creating new instances! R U MAD?!?!?!?!?!?!

    It made me nervous. Is creating these classes a bad thing? We are not writing here some serious, highly-performing stuff, just regular code that helps other people to solve their problems. I was really confused - is the guy right? Many people would say that object instantiation takes too much time in JVM. They are correct, however, the next question is: “How long?”.

    I needed to know. It is obviously an additional work to a computer but the advantage is significant for other programmers’ work. I had to test in on my own. Let’s do the microbenchmarking.

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