how to execute command from Java application?

Question

How to execute Windows or Linux commands from a Java application?

I want to run dir command from Java application without a command prompt.

How can this be done?

Answer 1

well .. you could do it with

Runtime.getRuntime().exec("...")

but you really don't want to ..

if you want to get a list of files in a directory use the File api! something like file.listFiles()

• ramana: Thanks for your answer. I am just asked dir command i need to execute all type of commands like make directory and some mail server command etc can i use same Runtime class?
• Herbert Poul: sure you can, just look at the linked api.. make sure to use the right methods.. so for example if you have multiple arguments make sure to pass a string array so you don't have to handle argument escaping yourself.. the returned Process class allows you to read the output / error stream from the started process, etc.

Answer 2

probably you may need to read output of executed app as well, if you need that

Process p = Runtime.getRuntime().exec("...");
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((line = br.readLine()) != null)
 System.out.println(line);

Answer 3

Just a note, dir is not an executable as such, but a command in the Windows command interpreter. To run dir, you would do Runtime.getRuntime().exec("cmd /C dir");