Adjust Java Library Path at Runtime (with Scala)

AdjustJavaLibraryPathAtRuntime.scala

object AdjustJavaLibraryPathAtRuntime {
 
  def addJavaLibraryPath(pathToAdd: String): Unit = {

    val oldPath = Option(System.getProperty("java.library.path"))

    // only add path if its not already included
    val newPath = oldPath.map(currentPath => if(!currentPath.contains(pathToAdd))
      pathToAdd + ":" + currentPath
    else
      currentPath
    )
      .getOrElse(pathToAdd)

    // set the system property
    System.setProperty("java.library.path", newPath)

    // force the refresh
    val field = classOf[ClassLoader].getDeclaredField("sys_paths")
    field.setAccessible(true)
    val oldRtPath = field.get(null)
    field.set(null, null) // this makes sure the pathes are refreshed
    field.set(null, oldRtPath) // make sure to do this, else java.nio will not work anymore!
  }
  
  
}