Creating a “.bat” file, run it and delete it from Java

Question

I'm making a .bat dynamically in Java .

After creating the file and exectuing it, I want to delete it.

In order to make sure that delete() will be executing after running the .bat file, I delete the file within a different thread.

Is this a good approach for this task? How would you implement it in a better way?

final File file = new File("run.bat");
file.createNewFile();
PrintWriter writer = new PrintWriter(file, "UTF-8");
writer.println(COMMAND1);
writer.println(COMMAND2);

.... ANOTHER COMMANDS

writer.close();
Runtime.getRuntime().exec("cmd /c start a.bat");

new Thread(new Runnable() {
    public void run() {
        file.delete();
    }
}).run();

Answer 1

I wouldnt delete the file in a different thread, what if the file execution is still running at the time you try to delete it?

I would consider asking the exit code from the file, or use a process.waitFor() which causes the current thread to wait, if necessary, until the process represented by this Process object has terminated.

Process p = Runtime.getRuntime().exec("cmd /c start a.bat");
p.waitFor();
file.delete();

Answer 2

Try this which causes the code to wait until the batch file execution is complete before deleting the file.

Process batchFileExecutionProcess = Runtime.getRuntime().exec("cmd /c start a.bat");
batchFileExecutionProcess.waitFor();
file.delete();

Ideally, you would build error handling into this solution as well, such as looking for a 0 return from the waitFor() method.

Answer 3

No, it's not good approach. Actually I don't see any advantage of the extra thread. Most likely it will attempt to delete the file while it's still being used by cmd and deletion will fail. Instead you should use Process object (the result of exec() ) and wait until the it finished and delete the file then:

Process p = Runtime.getRuntime().exec("cmd /c start a.bat");
p.waitFor();
file.delete()