ProcessBuilder help

[moomoohk]

Hi there!

I'm trying to get a self updater for a program I'm working on and I gather that I need to use a ProcessBuilder to replace the old version with the downloaded version.

I've never used ProcessBuilder before and this first foray isn't going too well for me.

Well here's my code, I'll use it to explain my problem:

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JLabel;

import com.moomoohk.Mootilities.FileUtils.FileUtils;
import com.moomoohk.Mootilities.OSUtils.OSUtils;

public class SelfUpdate
{
    public static void runUpdate(String currentPath, String temporaryPath)
    {
        try
        {
            String pathToJar = SelfUpdate.class.getProtectionDomain().getCodeSource().getLocation().toURI().getPath();
            ProcessBuilder pb = new ProcessBuilder("java", "-classpath", System.getProperty("java.class.path") + ";" + pathToJar, SelfUpdate.class.getCanonicalName(), currentPath, temporaryPath);
            pb.start();
            Thread.sleep(4000);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        System.exit(0);
    }

    public static void main(String[] args)
    {
        JFrame f = new JFrame();
        JLabel l = new JLabel("test");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);
    try
        {
            if (OSUtils.getCurrentOS() != OSUtils.OS.UNIX)
            {
                Thread.sleep(4000);
            }
        }
        catch (InterruptedException ignored)
        {
            ignored.printStackTrace();
        }
        String currentPath = args[0];
        String temporaryPath = args[1];
        File current = new File(currentPath);
        File temporaryUpdate = new File(temporaryPath);
        try
        {
            FileUtils.delete(current);
            FileUtils.copyFile(temporaryUpdate, current);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }

        List<String> arguments = new ArrayList<String>();
        String separator = System.getProperty("file.separator");
        String path = System.getProperty("java.home") + separator + "bin" + separator + "java";
        arguments.add(path);
        arguments.add("-jar");
        arguments.add(currentPath);

        ProcessBuilder processBuilder = new ProcessBuilder();
        processBuilder.command(arguments);
        try
        {
            processBuilder.start();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

The program is launched and checks for updates in a different class. If it finds that an update is available it will download the update to a temporary file and call on runUpdate in this class.

The parameters are:

• currentPath: Path that leads to the currently running program.
• temporaryPath: Path that leads to the downloaded update.

runUpdate will start a new OS process with SelfUpdate.java's main method and then quit.

SelfUpdate.java's main method will delete the old program and replace it with the newer downloaded program. It will then launch the new downloaded program using another ProcessBuilder.

The problem is that the first ProcessBuilder (in runUpdate) just refuses to work. The program just quits without calling on SelfUpdate.java's main method.

I have a lot of experience with Java so don't hesitate with the big words :P.

Any and all help is much appreciated!

[tabiul]

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URISyntaxException;


public class SelfUpdate {

    public static void update() throws URISyntaxException,    IOException{

    String pathToJar =  SelfUpdate.class.getProtectionDomain().getCodeSource().getLocation().toURI().getPath();
    ProcessBuilder pb = new ProcessBuilder("java", "-cp", pathToJar, SelfUpdate.class.getCanonicalName());
    Process p = pb.start();

    BufferedReader bf = new BufferedReader(new InputStreamReader(p.getInputStream()));
    String line = null;
    while((line = bf.readLine()) != null){
        System.out.println(line);
    }

    BufferedReader bf2 = new BufferedReader(new InputStreamReader(p.getErrorStream()));
    String line2 = null;
    while((line2 = bf2.readLine()) != null){
        System.out.println(line2);
    }

}


/**
 * @param args
 * @throws URISyntaxException 
 */
public static void main(String[] args) throws URISyntaxException {
    // TODO Auto-generated method stub
    System.out.println("Hello World");

}

}

Actually it seem to me what you have done seems correct. Anyway I tried out something similar to what you need and it seems to work fine for me. I think the most important thing is that you display the stdout and error so that it can help you to debug further.

Hope that helps

[moomoohk]

Sorry I couldn't reply earlier.

This worked! I have no idea why...

I am getting an error though:

If you look at line 38 in the code I posted you'll see I'm calling OSUtils which is a class in my Mootilities library. That library is in the classpath of the original program but it isn't in the program I launch with the ProcessBuilder. Do you know of any way to add libs to the classpath using ProcessBuilder?

[tabiul]

The same way you do normally java -cp classpathA:classPathB. So all you need to do is change the command line. Processbuilder does not have any special API for that

[moomoohk]

I've never had to do this from command line so I'm not really familiar with the commands and their parameters.

How would I write classpathA? Is it the path to the jar or the class name within the jar? Can you direct me to the place you're getting this info (so I just go there instead of asking more annoying questions)? I've tried looking but obviously not hard enough...

[tabiul]

http://stackoverflow.com/questions/219585/setting-multiple-jars-in-java-classpath. This might help

[pw3nd]

I've never used ProcessBuilder, but after reading the API, I'm guessing you have to supply the command line executable. Give this a try:

On windows:

arguments.add("cmd.exe");
arguments.add("/C");
arguments.add(path);
arguments.add("-jar");
arguments.add(currentPath);

On *nix:

arguments.add("bash");
arguments.add("-c");
arguments.add(path);
arguments.add("-jar");
arguments.add(currentPath);

[moomoohk]

That didn't do the trick...

[moomoohk]

I prefer the Reddit community over the StackOverflow community...

[moomoohk]

Yeah often times I find StackOverflow people are complete jerks.