Create Shapefiles from GeoJSON in Java with shapefile-creator
shapefile-creator is a lightweight library that converts GeoJSON into ESRI Shapefiles.
That is especially handy when GeoJSON is the exchange format in your application, but a downstream GIS workflow still expects a Shapefile export.
The key point is: you do not need anything else for that export. No additional GIS server, no heavyweight conversion toolchain, and no external desktop tooling in your application runtime. Just this library.
The library is published on Maven Central, so integration into existing Java or Groovy projects is straightforward.