Custom Audit Log With Spring And Hibernate

July 18, 2016

If you need to have automatic auditing of all database operations and you are using Hibernate…you should use Envers or spring data jpa auditing. But if for some reasons you can’t use Envers, you can achieve something similar with hibernate event listeners and spring transaction synchronization. First, start with the event listener. You should capture […]


Spring-Managed Hibernate Event Listeners

July 15, 2016

Hibernate offers event listeners as part of its SPI. You can hook your listeners to a number of events, including pre-insert, post-insert, pre-delete, flush, etc. But sometimes in these listeners you want to use spring dependencies. I’ve written previously on how to do that, but hibernate has been upgraded and now there’s a better way […]


Installing Java Application As a Windows Service

June 26, 2016

It sounds like something you’d never need, but sometimes, when you distribute end-user software, you may need to install a java program as a Windows service. I had to do it because I developed a tool for civil servants to automatically convert and push their Excel files to the opendata portal of my country. The […]


Why I Prefer Merge Over Rebase

June 17, 2016
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There are many ways to work with git. The workflows vary depending on the size of the team, organization, and on the way of working – is it distributed, is it sprint-based, is it a company, or an open-source project, where a maintainer approves pull requests. You can use vanilla-git, you can use GitHub, BitBucket, […]


Cleanup Temp Files

May 17, 2016

I’ve been spring-cleaning some devices and the obviousness of the advice in the title seems questionable. I found tons of unused temp files which applications (android apps, desktop applications and even server application deployments) haven’t cleaned. This is taking up space and it means more manual maintenance. For server-side applications the impact is probably smaller, […]


Dirty Hacks Are OK

May 12, 2016

In practically every project you’ve used a “dirty hack”. setAccessbile(true), sun.misc.Unsafe, changing a final value with reflection, copy-pasting a class from a library to change just one line of wrong code. Even if you haven’t directly, a library that you are using most certainly contains some of these. Whenever we do something like that, we […]


A Beginner’s Guide to Addressing Concurrency Issues

April 20, 2016

Inserts, updates and deletes. Every framework tutorial starts with these and they are seen as the most basic functionality that just works. But what if two concurrent requests try to modify the same data? Or try to insert the same data that should be unique? Or the inserts and updates have side-effects that have to […]


How To Read Your Passport With Android

April 5, 2016
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As I’ve been researching machine readable travel documents, I decided to do a little proof-of-concept on reading ePassports using an NFC-enabled smartphone (Android). The result is on GitHub, and is based on the jMRTD library, which provides all the necessary low-level details. As I pointed out in my previous article, the standards for the ePassports […]


Pretty Print JSON Per Request With Spring MVC

February 22, 2016

You will find a lot of posts and stackoverflow answers telling you how to pretty-print JSON responses. But sometimes you may need to tune the “prettiness” per request. The use case for this is when you are using tools like curl or RESTClient to interact with the system and you want human-readable output. Of course, […]


Setting Up Distributed Infinispan Cache with Hibernate and Spring

February 17, 2016

A pretty typical setup – spring/hibernate application that requires a distributed cache. But it turns out not so trivial to setup. You obviously need cache. There are options to do that with EhCache, Hazelcast, Infinispan, memcached, Redis, AWS’s elasticache and some others. However, EhCache supports only replicated and not distributed cache, and Hazelcast does not […]