Java Native Interface (JNI) allows you to call C code from Java code. There's a whole rigamarole of generating stubs, etc. But it works as far as I know. Don't know how robust it is though.

a gym gui code which uses the oop principal with gui based feature as well as event handleling to different methods used in the gym gui code - Prasiss/java-gui-code ...

GUI application written in Java designed to generate QR codes based on the entered text and logo. - Ggg93/QrGenerator ...