The file, jni.h provides the necessary information for C program to interact with java runtime. The header file is test.h, while stdio.h is the C library file that shows the output 'native'.

javah (java header) er maddhome header file (obviously java header file) create korte hbe and erpor same nam e akta C file create korte hobe. secondly shared_object (linux) / dll (windows) e create ...

You can also produce the declaring code (Java has no header files) from the compiled class files. Those compiled class files can be distributed under any license you want (GPL Classpath exception).