lwjgl load natives

/**
 * Based on http://frommyplayground.com/how-to-load-native-jni-library-from-jar by Adam Heirnich <adam@adamh.cz>
 */
public class NativeUtils {

    private final static String DIR_NATIVES = "lwjgl-natives";

    private NativeUtils() {}

    public static File createTempDir() throws IOException {
        final File tempDir = File.createTempFile(DIR_NATIVES, "");
        tempDir.delete();
        tempDir.mkdir();
        tempDir.deleteOnExit();

        return tempDir;
    }

    public static void loadLibraryFromJar(File parent, String library) throws IOException {
        if (!library.startsWith("/")) throw new IllegalArgumentException("The path to be absolute (start with '/').");

        final String filename = library.substring(library.lastIndexOf('/'));            // Obtain filename from path

        if (filename == null)                                                           // Check if the filename is okay
           throw new IllegalArgumentException("The filename has to be at least 3 characters long.");

        final File temp = new File(parent, filename);                                   // Prepare temporary file
        temp.createNewFile();
        temp.deleteOnExit();

        if (!temp.exists()) throw new FileNotFoundException("File " + temp.getAbsolutePath() + " does not exist.");

        final byte[] buffer =   new byte[1024];                                         // Prepare buffer for data copying
        int readBytes =         0;

        final InputStream is = NativeUtils.class.getResourceAsStream(library);          // Open and check input stream
        if (is == null)
            throw new FileNotFoundException("File " + library + " was not found inside JAR.");

        final OutputStream os = new FileOutputStream(temp);                             // Open output stream and copy data between
        try {                                                                           // source file in JAR and the temporary file
            while ((readBytes = is.read(buffer)) != -1)
                os.write(buffer, 0, readBytes);
        } finally {                                                                     // If read/write fails, close streams
            os.close();                                                                 // safely before throwing an exception
            is.close();
        }
    }

    public static void deleteOldDir() {
        final FileFilter tmpDirFilter = new FileFilter() {
            public boolean accept(File pathname) {
                return pathname.getName().startsWith(DIR_NATIVES);
            }
        };

        final String tmpDirName = System.getProperty("java.io.tmpdir");
        File[] tmpFiles = new File(tmpDirName).listFiles(tmpDirFilter);

        for (File f : tmpFiles) delete(f);
    }

    private static void delete(File file) {
        if (file.isDirectory())
            for (File f : file.listFiles())
                delete(f);
        else file.delete();
    }
}