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Customizing HttpMessageConverters with Spring Boot and Spring MVC


Exposing a REST based endpoint for a Spring Boot application or for that matter a straight Spring MVC application is straightforward, the following is a controller exposing an endpoint to create an entity based on the content POST’ed to it:                 @RestController @RequestMapping("/rest/hotels") public class RestHotelController { .... @RequestMapping(method=RequestMethod.POST) public Hotel create(@RequestBody @Valid ...

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Using Infinispan as a persistency solution


Cross-posted from Thanks Fredrik and Matti for your permission! Various RDBMSs are the de-facto standard for persistency. Using them is such a safe bet by architects that I dare say they are used in too many places nowadays. To fight against this, I have recently been exploring with alternative persistency options, like graph databases. This time I played with Infinispan. ...

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Using Gradle to Build & Apply AST Transformations


Recently, I wanted to both build and apply local ast transformations in a Gradle project. While I could find several examples of how to write transformations, I couldn’t find a complete example showing the full build process. A transformation has to be compiled separately and then put on the classpath, so its source can’t simply sit in the rest of ...

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An Inconvenient Latency


Overview Vendors typically publish numbers they are happy with, and avoid telling you about a product’s weaknesses.  However, behind the numbers is a dirty secret if you know where to look. Why don’t we use GPUs for everything? Finding problems which naturally scale to thousands of data points/tasks is easy for some problems, and very hard for others.   GPUs ...

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R: Calculating rolling or moving averages


I’ve been playing around with some time series data in R and since there’s a bit of variation between consecutive points I wanted to smooth the data out by calculating the moving average. I struggled to find an in built function to do this but came across Didier Ruedin’s blog post which described the following function to do the job: ...

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Load Balance WebSockets using Apache HTTPD


JBoss EAP 6.3 provides a technology preview of WebSocket and WildFly have supported them as part of Java EE 7 compliance. provide tons of Java EE 7 samples that run on WildFly. If you are interested in similar functionality on JBoss EAP 6.3 then is a quickstart. In addition, there are a few more samples at One of the common questions ...

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JUnit Rules


Introduction In this post I would like to show an example of how to use JUnit Rule to make testing easier. Recently I inherited a rather complex system, which not everything is tested. And even the tested code is complex. Mostly I see lack of test isolation. (I will write a different blog about working with Legacy Code). One of ...

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An open web application framework benchmark


Selecting a platform for your next application development project can be a complex and burdensome undertaking. It can also be very intriguing and a lot of fun. There’s a wide range of different approaches to take: at one end The Architect will attend conferences, purchase and study analyst reports from established technology research companies such as Gartner, and base his ...

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Runtime Class Loading to Support a Changing API


I maintain an IntelliJ plugin that improves the experience of writing Spock specifications. A challenge of this project is supporting multiple & incompatible IntelliJ API versions in a single codebase. The solution is simple in retrospect (it’s an example of the adapter pattern in the wild), but it originally took a bit of thought and example hunting. I was in ...

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Friday-Benchmarking Functional Java


Lets image our product owner goes crazy one day and ask to you to do the following : From a set of Strings as follows : "marco_8", "john_33", "marco_1", "john_33", "thomas_5", "john_33", "marco_4", .... give me a comma separated String with only the marco's numbers and numbers need to be in order. Example of expected result : "1,4,8"     ...

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