Trying to run an application from Java

Question

I need to run the "VBoxManage vms list command" to see the virtual machines installed on a computer from a Java application.

The following code works correctly but only if I use the Runtime class but I would like to know why it fails if I use ProcessBuilder.

The code is the following:

public static void main(String[] args) throws IOException {
 String folder= "c:/Program files/Oracle/VirtualBox";
 List<String> comand = Arrays.asList(
 "VBoxManage",
 "list",
 "vms" 
 );
 ProcessBuilder pb = new ProcessBuilder()
 .directory(new File(folder))
 .command(comand);
 Process p = pb.start();
 BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
 String line;
 while((line=br.readLine()) != null){
 System.out.println(line);
 }
}

This works fine if I use the Runtime class with this code: Runtime runtime = Runtime.getRuntime(); Process p = runtime.exec("c:/Program files/Oracle/VirtualBox/vboxmanage list vms");

Thank you.

• Kayaman: Fails how exactly?
• Turamarth: You use a different case for the name of the program with the ProcessBuilder. VBoxManage vs. vboxmanage
• Alberto: I tryed both but doesn't work
• Alberto: java indicates that can't find the application

Answer 1

Try using the full path of the executable, like you do when using Runtime.exec

List<String> comand = Arrays.asList(
 "c:/Program files/Oracle/VirtualBox/VBoxManage",
 "list",
 "vms" 
);

• Alberto: This way it works correctly but I don't understand the reason. In the code I provide, I indicate the directory where you have to run the application. In fact, if instead of trying to run vBoxManager I run a "dir", it works correctly on the indicated directory.
• Joni: When you try to run VBoxManage the operating system looks for an executable file called VBoxManage.exe in a few folders. "c:/Program files/Oracle/VirtualBox" is not one of them and that's why you get the error. The list of folders is controlled by "PATH environment variable" - search for that phrase to learn more. "Directory" would set the program's current working directory, it does not help the operating system find the executable.
• Alberto: I'm sorry but I still don't understand the problem. Using the "directory" method, I indicate the working directory where the application I want to run is, and even then, it does not run it. Instead, it does run a "dir", for example