Native Utils

A simple library class which helps with loading dynamic libraries stored in the JAR archive. These libraries usualy contain implementation of some methods in native code (using JNI - Java Native Interface).

Notes

• The temporary file is stored into temp directory specified by java.io.tmpdir (by default it’s the operating system’s temporary directory). It should be automatically deleted when the application exits.
• Although the code has some try-finally section (to be sure that streams are closed properly in case an exception is thrown), it does not catch exceptions. The exception has to be handled by the application. I belive this approach is cleaner and has some benefits.

Usage

To load the dynamic library, just make sure it is packed inside the JAR archive and call method loadLibraryFromJar:

import cz.adamh.NativeUtils;

public class HelloJNI {  
    static {   
        try {    
            NativeUtils.loadLibraryFromJar("/resources/libHelloJNI.so");   
        } catch (IOException e) {
            // This is probably not the best way to handle exception :-)    
            e.printStackTrace();
        }    
    }  

    public native void hello();    
}

More information

More information can be found in accompanying blog post.