Refactoring and DB Independence with Oliver Gierke and Stefan Holzknecht
At 20th February we were delighted to be visited by Oliver Gierke, the first Java Champion talking at our roughly one year old user group. (At the next event we might need a birthday cake. Feel free to bake and deliver one!)
This time we were invited to the 21st floor of the great JenTower by Intershop Communications, which also fosters a comprehensive tech blog to showcase their development approaches and give something back to the community, including their Travel Transformer.
The evening basically consisted out of 3 big blocks:
- Introductions: Java User Group Thüringen and Softwerkskammer Jena by Benjamin Nothdurft, Stammtisch IT-Sicherheit by Dr. Anja Beyer-Peters, Intershop by Johannes Metzner.
- Talklet: Mastering DB Independence by Stefan Holzknecht
- Talklet: Refactoring to a system of systems by Oliver Gierke
As a start we delivered a short introduction talk (slides) to inform about upcoming events at our JUG Thüringen and the next events of our partner group Softwerkskammer Jena.
Besides that we were happy to welcome the quite new special interest group “Stammtisch IT-Sicherheit Jena”. Hence, we invited Anja, a local Security Expert at T-Systems MMS, who founded the meetup in cooperation with Prof. Dr. Zehender, chair of Advanced Computing at the Friedrich Schiller University Jena. She explained briefly the basic ideas and the current schedule with quarterly meetups. Their next/third event will happen on 25th of April and include a background presentation about the electronic identity card (“Elektonischer Personalausweis”).
Johannes Metzner, who helped with Dagmar and others at the organization of the evening, kicked off the presentations. We were happy to get these insights into the R’n’D department of Intershop at first hand.
Johannes explained that besides the flagship product, which pioneered commerce management since the 2000s, a small team also develops an order management solution, which uses Spring. That fact fits of course quiet nicely with our guest Oliver, who is the Spring Data team lead at Pivotal.
Stefan Holzknecht explained in his talklet “Mastering DB Independence” how Intershop dealt with supporting multiple databases and outlined their evolutionary path (with many tools) towards their current state. You can find out more in this video recording.
Oliver Gierke delivered his keynote-proven talklet on Refactoring to a system of systems. He showed a typical migration path of a large-scale project. More or less by coincidence, this sample project is a shop system, which was quite amusing to our 50+ visitors of whom most work within the eCommerce domain (wink, wink). The leading questions and typical systems states were:
- (1) Monolith (Big Ball of Mud): What are typical Bounded Context interactions in a monolithic applications?
- (2) Microlith (The Careless Microservice): What happen if these patterns are tralslated 1:1 into a distributed system?
- (3) Modulith: Can we build a better monolith in the first place?
- (4) System of Systems: How to translate that new approach into a distributed system?
You may checkout the full video recording, the slides and sample code online. If you are still unfamiliar with Domain-driven Design, you may also read this free short book.
Always keep in mind that there is no perfect tool nor framework, language or process. Thus, visit us at our next events to keep on learning!
