Stack: MySQL/Java/Spring/Maven/Linux/Docker/Google Web Toolkit
MySQL: most data are JSON blobs, it's convenient for document-oriented data models and supported well in Java and GWT. Mysql supports JSON and tabular views on top, which is super-convenient for queries.
Java: especially since records and lambdas entered the language, it's nice to work with. Strong typing is an added bonus. Excellent ecosystem, good testing tools for the entire stack (unit testing up to end-to-end testing).
Spring: abstracts away a lot of functionality (JSON-to-objects, authentication, web serving, database handling, dependency injection) that I would have to otherwise implement myself or through 3rd party libs
Maven: there are better and faster build tools, but I kind of missed the train there. I don't use a CI/CD server, just a docker container with Maven that builds app images
Linux: the best OS if you run open source software.
Docker: my personal projects don't justify the complexity of k8s, also public cloud is too expensive.
Google Web Toolkit: imho the most misunderstood web framework out there. Google had the right hunch but destroyed it by adding too many esoteric features. I use GWT as a java-to-javascript compiler and for the excellent DOM abstractions which allows me to write fairly complex applications with a very low bug count.
On the front-end, I’ll take whatever comes. I have dabbled with React, but not enough to get beyond the nagging feeling that it has the potential to become 1990s PHP.