The Elasticsearch Learning to Rank plugin uses machine learning to improve search relevance ranking. It's powering search at places like Wikimedia Foundation and Snagajob.
The modern, next-generation Minecraft server proxy
...The software is designed with a focus on performance, scalability, and modern architecture, allowing it to handle thousands of simultaneous players efficiently. Velocity also includes a plugin API that allows developers to extend the proxy with custom functionality and integrate it with existing server tools. Compared with older proxy solutions, the project emphasizes improved performance, reliability, and cleaner software design.
An engine-agnostic deep learning framework in Java
...You can use your existing Java expertise as an on-ramp to learn and use machine learning and deep learning. You can use your favorite IDE to build, train, and deploy your models. DJL makes it easy to integrate these models with your Java applications. Because DJL is deep learning engine agnostic, you don't have to make a choice between engines when creating your projects. You can switch engines at any point. To ensure the best performance, DJL also provides automatic CPU/GPU choice based on hardware configuration.