Bagatur chess engine is one of the strongest Java chess engines in the world. It is also available for Android via Bagatur Chess Engine with GUI game, which has its own user interface. If you like the project, please give it a star.
The latest release runs under all Operating Systems, which support Java platform.
The source code is writen entirely in Java programming language.
The ELO rating is an important metric for a chess engine.
There are some code examples of Artificial Intelligence / Machine Learning experiments with the Neuroph 2.94 Java framework. The starting point into the source code is located here and the documentation is here. Although the ELO strength of the experimential version is with 50 ELO less than the version with the manually tuned evaluation function's parameters, the results are successful meaning that the neural network's backpropagation algorithm works as expected for multi layer perceptron neural network. This makes the experiments a good showcase of Neuroph Java framework.
The author of Bagatur engine is Krasimir Topchiyski.