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.

Maven

You need a Github account and a personal access token to build against Github's Maven Repo.

Add the following dependency and repository to your pom.xml:

<dependencies>
    ...
    <dependency>
        <groupId>cz.adamh.utils</groupId>
        <artifactId>native-utils</artifactId>
        <version>1.0</version>
    </dependency>
</dependencies>
...
<repositories>
    <repository>
        <id>github</id>
        <name>GitHub regwhitton Apache Maven Packages</name>
        <url>https://maven.pkg.github.com/regwhitton/native-utils</url>
    </repository>
</repositories>

Create a Github personal access token. See Creating a personal access token for the command line

Edit your ~/.m2/settings.xml and add a server entry.

<settings ...>
    ...
    <servers>
        <server>
            <id>github</id>
            <username>your_github_username</username>
            <password>your_github_access_token</password>
        </server>
    </servers>
    ...
</settings>