JNI, The Java Native Interface
Standard programming interface for writing Java native methods and embedding the Java virtual machine into native applications.
Website: http://download.oracle.com/javase/6/docs/technotes/guides/jni/index.html, http://java.sun.com/docs/books/jni/
Platforms supported: Win32, Linux
Headers to include: jni.bi
Header version: from 2006
Examples: in examples/other-languages/Java/
Examples:
Three files:
- mylib.bas - A DLL writting in FreeBASIC
#include "jni.bi"
'' Note: The mangling must be "windows-ms" or the JRE won't find any function
Extern "windows-ms"
Function Java_MyLib_add( env As JNIEnv Ptr, obj As jobject, l As jint, r As jint ) As jint Export
Return l + r
End Function
End Extern
'' Note: The mangling must be "windows-ms" or the JRE won't find any function
Extern "windows-ms"
Function Java_MyLib_add( env As JNIEnv Ptr, obj As jobject, l As jint, r As jint ) As jint Export
Return l + r
End Function
End Extern
- Mylib.java - The Java class that represents the interface to the FreeBASIC code and ensures the FreeBASIC DLL is loaded
class MyLib {
public native int add( int l, int r );
static {
System.loadLibrary( "mylib" );
}
}
public native int add( int l, int r );
static {
System.loadLibrary( "mylib" );
}
}
- Test.java - The Java main() that uses the Mylib class
class Test {
public static void main(String[] args) {
MyLib lib = new MyLib();
System.out.println( "2+2=" + lib.add( 2, 2 ) );
}
}
public static void main(String[] args) {
MyLib lib = new MyLib();
System.out.println( "2+2=" + lib.add( 2, 2 ) );
}
}
Steps to test it:
- Compile the FreeBASIC DLL: fbc mylib.bas -dll
- Compile the two Java classes: javac Mylib.java Test.java
- Run the Test class: java Test
