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.