java - How to set working directory with ProcessBuilder

Question

I am trying start a process in my home directory in ubuntu. I keep getting a permission denied exception and I have no idea why. Here is the code:

Process p = null;
ProcessBuilder pb = new ProcessBuilder("/home");
p = pb.start();

Here is the exception:

Exception in thread "main" java.io.IOException: Cannot run program "/home": 

java.io.IOException: error=13, Permission denied
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:475)
        at tester.Main.main(Main.java:30)
Caused by: java.io.IOException: java.io.IOException: error=13, Permission denied
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:164)
        at java.lang.ProcessImpl.start(ProcessImpl.java:81)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:468)
        ... 1 more
Java Result: 1

Answer 1

You are trying to execute /home and it is not an executable file. The constructor argument of the process builder is the command to execute.

You want to set the working directory. You can that it via the directory method.

Here is a complete example:

Process p = null;
ProcessBuilder pb = new ProcessBuilder("do_foo.sh");
pb.directory(new File("/home"));
p = pb.start();