This has been a long term tech-debth but with the service changing the definition of the free plan every now and then, we should better be free of such dependency. This month, the service started sending notifications we are running out of message number quota.

On a first glance, mailhog has a container[1] and there are some bindings for java[2], albeit unreleased.

[1] https://hub.docker.com/r/mailhog/mailhog/
[2] https://github.com/tomphp/java-mailhog-client