0

I have a program with the following code:

import java.io.File;
import javax.swing.JOptionPane;

public class Main {

    public static void main(String[] args) {
        File file = new File("config");
        JOptionPane.showMessageDialog(null, file.getAbsolutePath());
        System.out.println(file.getAbsolutePath());
    }
}

I export this as a Runnable Jar in eclipse. Then I copy the file to /home/username/Desktop/ on my Ubuntu 13.04 system and cd to that directory. When I run the command java -jar Main.jar, I get the following output:

/home/username/Desktop/config

Now I run chmod to make the Jar executable, and then I go and double click on the Jar. I get the following output from the dialog:

/home/username/config

Why am I getting different output? Moving the Jar to other directories result in similar results. Googling and searching SO shed no light on this issue.

ajduke
  • 4,991
  • 7
  • 36
  • 56
gsgx
  • 12,020
  • 25
  • 98
  • 149

1 Answers1

2

new File("config") is relative to the working directory of the process running the JVM. When you run from the command line after cd 'ing into the directory then that is the working directory.

Double clicking the jar from the Ubuntu GUI is not setting the working directory to the same directory that houses the jar file, thus the difference.

Try this:

cd into /home/username from the command like, then type java -jar Desktop/Main.jar. That will print out the same as when you double clicked on the jar.

If you would like to get the same directory each time, then use an absolute directory name. On Linux one does this by starting the directory with a /. eg new File("/home/username/config"). If you want to find the users home directory dynamically then use System.getProperty("user.home").

eg new File( System.getProperty("user.home") + "/config" );

Chris K
  • 11,622
  • 1
  • 36
  • 49
  • I concur with this response. – le3th4x0rbot Apr 11 '13 at 18:12
  • I want to get paths relative to where the Jar file is regardless of how it is launched, so I don't want an absolute path. I think this is what I want: http://stackoverflow.com/questions/320542/how-to-get-the-path-of-a-running-jar-file. But anyway, your answer helped me figure out what was going on, so thanks. – gsgx Apr 11 '13 at 18:21