Description

JNativeLibLoader' is a powerful library with a simple API to load native libraries (.dll, . so) from JAR files into the JVM for java applications which need to invoke native code via jni in a platform independend manner.

This includes:

1. unpacking binary native library files from the JAR to a cache.
2. recognizing the platform the using application is running at.
3. loading the binary native library files into the jvm depending on the platform.

The native libs bundled within the JAR will be loaded in the right sequence if they mutually depend on each other. But loading will fail if their dependency graph contains cycles.

More Developer Info here.

Limitation

At the moment only Linux x86-64 and Windows x86-64 are supported

Credits

Much source code originates in an extraction of the Gluegen project from 15.09.2020.
Customized Gluegen source code is located within folders named “jogamp”.
You can find the full source code of the Gluegen project here: https://github.com/JogAmp/gluegen.
The copy of the Gluegen license is in the file Gluegen_LICENSE.txt.

Tested prerequisites

• Netbeans 12
• Java SDK 11
• Maven

How to use it

Clone the repository and build the project. This will add JNativeLibLoader to the local Maven cache. You only need to rebuild JNativeLibLoader if you change it's codebase.

Then follow the steps in the next section to configure your project.

Exemplary project: JViconDataStream2.

Configure your project

Add to Maven pom

If you are not familiar with Maven, search the internet how to properly include these snippets:

<dependency>
	<groupId>de.orat.rahmlab</groupId>
	<artifactId>NativeLibLoader</artifactId>
	<version>1.0-SNAPSHOT</version>
</dependency>

<resource>
	<targetPath>${basedir}/target/classes/natives</targetPath>
	<directory>${basedir}/natives</directory>
</resource>

Add native files

Your project structur should look something like this:

Myproject
|- natives
   |- linux-amd64
      |- <.so files here>
   |- windows-amd64
      |- <.dll files here>
|- src
|- ...

Load them in your code

Make sure that you load the native files before you invoke any jni code and that you load them only once.

Snippets:

import de.dhbw.rahmlab.nativelibloader.api.NativeLibLoader;

NativeLibLoader.init(true);
NativeLibLoader nativeLibLoader = NativeLibLoader.getInstance();
nativeLibLoader.load(MyClass.class);

Substitute MyClass with any class from your project. If you generate multiple JAR's make sure that MyClass is in the same JAR as the native files.

Big JAR

To make deployment easy it can be a good idea if you bundle your project code, your native libs and the JNativeLibLoader' functionality into one single JAR file.

A way to do this is to configure maven-assembly-plugin to build a jar-with-dependencies.
You can find examples for this procedure e.g. here: https://stackoverflow.com/questions/574594/how-can-i-create-an-executable-jar-with-dependencies-using-maven.