https://jensknipper.de/blog/ Recent content in Blogs on Jens Knipper https://jensknipper.de/%3Clink%20or%20path%20of%20image%20for%20opengraph,%20twitter-cards%3E https://jensknipper.de/%3Clink%20or%20path%20of%20image%20for%20opengraph,%20twitter-cards%3E Hugo en Mon, 19 Jan 2026 01:00:00 +0000 https://jensknipper.de/blog/demystifying-dependency-injection-what-and-why/ Mon, 19 Jan 2026 01:00:00 +0000 https://jensknipper.de/blog/demystifying-dependency-injection-what-and-why/ Most projects use Dependency Injection in some form. However, many developers take it for granted and do not really question what it is or why they are using it in the first place. This article aims to answer those questions, even though they are rarely asked. https://jensknipper.de/blog/gitlab-ci-pages-asciidoc-documentation-as-code/ Thu, 03 Apr 2025 01:00:00 +0000 https://jensknipper.de/blog/gitlab-ci-pages-asciidoc-documentation-as-code/ Writing documentation should be as low-key as possible to remove the pain from the process. One way to achieve this is through Documentation as Code. Setting it up and configuring it may take some time, but once it's done, you can focus on creating the content itself. https://jensknipper.de/blog/roundcube-sieve-filter-attachments/ Mon, 08 Jul 2024 01:00:00 +0000 https://jensknipper.de/blog/roundcube-sieve-filter-attachments/ I was recently the target of a phishing attack using fake invoices. They were easy to spot, but it was still annoying that they were landing in my inbox. So, I wanted to create a solution where these emails would not bother me anymore. https://jensknipper.de/blog/java-aktuell-lambda-testing-article/ Tue, 25 Apr 2023 01:00:00 +0000 https://jensknipper.de/blog/java-aktuell-lambda-testing-article/ Nachdem ich über das Thema auf der JavaLand einen Talk gehalten habe, habe ich die Chance bekommen das Ganze in Form eines Artikels in einer Zeitschrift zu veröffentlichen. https://jensknipper.de/blog/openvalue-meetup-lambda-testing-talk/ Thu, 10 Nov 2022 01:00:00 +0000 https://jensknipper.de/blog/openvalue-meetup-lambda-testing-talk/ Last week I hold my talk "Local testing of AWS serverless lambda functions" at a virtual meetup of OpenValue. In this post, you can find the slides and the recording of my talk. https://jensknipper.de/blog/speaker-javaland-newcomer/ Fri, 07 Oct 2022 01:00:00 +0000 https://jensknipper.de/blog/speaker-javaland-newcomer/ I struggled with a problem at work, was able to solve it neatly and thought it would make a great topic for a talk or a blog article. So I applied at the call for papers of the JavaLand newcomer program with it and got accepted! https://jensknipper.de/blog/traefik-logging/ Thu, 11 Aug 2022 01:00:00 +0000 https://jensknipper.de/blog/traefik-logging/ In this article I will show you how to activate logging in Traefik. There are two kinds of logs in Traefik, the general log and the access log. We will have a look at both of them and take a deeper look into the possibilities they provide. https://jensknipper.de/blog/receiving-emails-in-java/ Mon, 30 May 2022 01:00:00 +0000 https://jensknipper.de/blog/receiving-emails-in-java/ I was recently in need to write some small demo project which was receiving and processing mails. There is a lot of documentation for sending mails, but gathering information about the receiving and processing part is less easy. https://jensknipper.de/blog/traefik-redirect-to-external-domain/ Sun, 03 Apr 2022 01:00:00 +0000 https://jensknipper.de/blog/traefik-redirect-to-external-domain/ Redirecting to another domain is a regular use case I need a lot. Luckily Traefik makes it easy to implement it. https://jensknipper.de/blog/fix-ssh-folder-file-permissions/ Mon, 28 Jun 2021 01:00:00 +0000 https://jensknipper.de/blog/fix-ssh-folder-file-permissions/ I recently got an error on my work machine when copying ssh keys from Windows into WSL Linux. The error stated that the permissions were to open for my private key. https://jensknipper.de/blog/openvalue-meetup-greenmail-talk/ Sat, 05 Jun 2021 01:00:00 +0000 https://jensknipper.de/blog/openvalue-meetup-greenmail-talk/ Last week I hold my talk "Testing email with GreenMail, a mock mail server" at a virtual meetup of OpenValue. In this post, you can find the slides and the recording of my talk. https://jensknipper.de/blog/exposing-traefik-dashboard/ Sun, 16 May 2021 01:00:00 +0000 https://jensknipper.de/blog/exposing-traefik-dashboard/ The Traefik dashboard is the central place where everything you configured is represented in a clear manner. In case you are running into problems and you are in need to do some troubleshooting, the dashboard should be your place to go. https://jensknipper.de/blog/basic-authentication-with-traefik/ Thu, 15 Apr 2021 01:00:00 +0000 https://jensknipper.de/blog/basic-authentication-with-traefik/ Adding authentication to a service that does not support it by default can be done easily by using Traefik. This way you gain an additional layer of security and you can leverage other features of Traefik like domain names. https://jensknipper.de/blog/greenmail-mock-mail-server-dev-setup/ Tue, 16 Feb 2021 01:00:00 +0000 https://jensknipper.de/blog/greenmail-mock-mail-server-dev-setup/ Are you sending mails featured with HTML and CSS and want see how they look before pushing your changes to production? You also do not want mails to leak from your local environment to your customer? A mock mail server like GreenMail might just be the tool you need. https://jensknipper.de/blog/dealing-with-generic-fields-in-jcodemodel/ Wed, 14 Oct 2020 01:00:00 +0000 https://jensknipper.de/blog/dealing-with-generic-fields-in-jcodemodel/ Another article about JCodeModel. This time we will make a short excursion about how to generate generic fields in JCodeModel. https://jensknipper.de/blog/generating-enums-in-java-with-jcodemodel/ Sun, 11 Oct 2020 01:00:00 +0000 https://jensknipper.de/blog/generating-enums-in-java-with-jcodemodel/ This article will show you how to generate your own enum classes with jCodeModel. A framework to generate java classes. https://jensknipper.de/blog/using-maven-in-wsl/ Fri, 03 Jul 2020 01:00:00 +0000 https://jensknipper.de/blog/using-maven-in-wsl/ Installing and configuring Maven on Windows does not have to be a pain anymore. Thanks to the WSL it becomes almost as straightforward as using Linux. Although depending on your use case there might be some restrictions. https://jensknipper.de/blog/traefik-regex-testing/ Sun, 17 May 2020 20:00:00 +0000 https://jensknipper.de/blog/traefik-regex-testing/ Testing regular expressions for application configuration is always a pain as every programming language has a slightly different implementation. This results in expressions giving different results for different applications. https://jensknipper.de/blog/traefik-http-to-https-redirect/ Sat, 02 May 2020 12:00:00 +0000 https://jensknipper.de/blog/traefik-http-to-https-redirect/ This article covers the basic examples how to redirect HTTP-requests to HTTPS. This can be achieved per domain, for a single application only or globally for all containers.