This project is set up to build a consumable Jar library that bundles built-in rtmidi binaries from the fairly up to date (i.e. not outdated) sources, and then bundle them within a Jar using jnaerator-gradle-plugin (of my fork).
I set this up primarily for ktmidi project.
If you use rtmidi-jna as a Maven package, use this line In build.gradle:
implementation "dev.atsushieno:rtmidi-jna:+" // replace + with a specific version
The Maven package is built and packaged by the GitHub Actions setup in this repository, and contains prebuilt rtmidi binaries for Linux x86_64, Windows x86_64, and MacOS x86_64. For anything else, you are supposed to prepare your own (lib)rtmidi shared/dynamic library. Also note that rtmidi does not seem to respect full ABI compatibility.
An important note here is that with the current JNAerated package, those bundled libraries turned out to not get extracted and placed to any appropriate location. Therefore you will have to appropriately set up those shared libraries in the library paths for each platform (e.g. using LD_LIBRARY_PATH). Sadly JNAerator has been unmaintained and there is little chance to get this working.
rtmidi-jna is distributed under the MIT licanse.
rtmidi is also distributed under the MIT license.