Launch runnable run from native java application

Question

I currently have the following problem:

I have two java applications: updater and client. The updater is a native application (which contains the necessary JDK), while the client is just a runnable jar file.

When the user starts the application, it basically starts the updater, which searches for an update for the client application on the server. When a new update is present, the updater downloads the update and places it in a file (or overwrites the current jar file). Then, I execute the downloaded .jar file like this:

private void startApplication() {

    Runtime rt = Runtime.getRuntime();
    try {
        Process pr = rt.exec("java -jar libs/myJar.jar");
    } catch (IOException e) {
        e.printStackTrace();
    }
}

This works fine when building and running in Eclipse, but when I run the native application (which is built by Eclipse) myJar.jar doesn't get executed. I think it is due to the fact that the updater can not find the jar file, because it absolute path becomes different.

My question: How can I make sure that the native application can execute the downloaded jar file?

Note: I am currently building the app on Mac OSX, so I am testing this with a .dmg. I don't know if the problem is also present for Windows or Linux.

Edit 1: It doesn't seem to be a problem with the path, because this seems to be fine (as tested with @Funtik, thank you for that).

Edit 2: The file permissions also seem to be correct. Maybe it has something to do with the fact that the client jar doesn't know which JVM to use?

Answer 1

You have to use absolute path for this.

 String path = new File(".").getAbsolutePath();
 Process pr = rt.exec("java -jar "+ path + "/libs/myJar.jar");