{{fbdoc item="title" value="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/

{{fbdoc item="ex"}}

	Three files:

	- ##mylib.bas## - A DLL writting in ""FreeBASIC""

	{{fbdoc item="filename" value="examples/manual/libraries/jni/mylib.bas"}}%%(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%%

	- ##Mylib.java## - The Java class that represents the interface to the ""FreeBASIC"" code and ensures the ""FreeBASIC"" DLL is loaded

	{{fbdoc item="filename" value="examples/manual/libraries/jni/Mylib.java"}}%%(cpp)
class MyLib {
	public native int add( int l, int r );
	static {
		System.loadLibrary( "mylib" );
	}
}
%%

	- ##Test.java## - The Java main() that uses the Mylib class

	{{fbdoc item="filename" value="examples/manual/libraries/jni/mylib.bas"}}%%(cpp)
class Test {
	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##

{{fbdoc item="back" value="ExtLibTOC|External Library Table of Contents"}}