run command prompt cmd in java

Unfortunately it is not that simple like just running Runtime.exec(). If the application outputs any data that function may hang waiting until you read all the characters from the input stream. It depends on how much data the application outputs, for short output like 'ok' it may work fine though as a few characters can be stored in the buffers.

Another problem with this is is the external command hangs for some reason (waiting for user input) your application may hang too so the best way is to execute it in a separate thread.

An example code to run the external command would be:

java.lang.Process proc = Runtime.getRuntime().exec(cmd);
InputStream proc_out = proc.getInputStream();
InputStream proc_err = proc.getErrorStream();
// Here you have to read from both input streams
// I deall in a separate threads
try {
    proc.waitFor();
} catch (InterruptedException e) { } // end of try-catch
proc_out.close();
proc_err.close();
return proc.exitValue();