runtime exec of command.com mkdir malfunction

[John Davis]

If I get a command.com window and execute

 mkdir c:\abcdefghi 

it works perfectly. (I'm on an XP Home System)
But when I run a Java app to do the same thing via
runtime.exec() as in:

 
 
Runtime rt = Runtime.getRuntime();
 
Process mdProc = rt.exec("command.com /c md C:\\ABC");

StreamGobbler errorGobbler = new
                StreamGobbler(mdProc.getErrorStream(), "ERROR");            

StreamGobbler outputGobbler = new
           StreamGobbler(mdProc.getInputStream(), "OUTPUT");

    errorGobbler.start();

    outputGobbler.start();
 
    int exitVal = mdProc.waitFor();

    System.out.println("Process exitValue: " + exitVal);

     String newline = "\n";

textArea.append("returnCode from md = " + exitVal + " . . .  0 means md success " + newline);
       }
catch (Throwable t)
         {
            t.printStackTrace();
          }
 
 

then the make directory command is limited to creating directories that have a maximum of 8 characters in their name.

Why is this? And how can I get the runtime.exec() process to execute a command.com mkdir internal command intrepeter command that creates directories with 9 or more characters?

[Ernest Friedman-Hill]

And you can't use CMD.EXE because...? Or, for that matter, java.io.File.mkdir() ?

[John Davis]

Ernest,

I tried cmd.exe and everything worked perfectly. Thanks very much for your input.
I'm going to be using cmd.exe for a long list of function invocations in the windows environment some of which don't nave a java equivalent (such as net stop and start for windows services), so I wanted to be consistent in my Java app.

However, I would appreciate further information as to what needs to be considered when choosing between command.com and cmd.exe. My information (which is obviously sketchy and flawed) was that cmd.exe should be used for NT and command.com for everything else (Windows 95, 98, XP, ME, etc.).
This is obviously incorrect and I would very much like to be set straight on this matter.

[Ernest Friedman-Hill]

To answer your last question: you're correct except that you put XP in the wrong pile. If Windows 2000 was NT 5, then XP is "NT 6". 95/98/ME basically follow the old "shell on top of DOS" model, whereas the NT OSs are a complete OS in themselves.

[Stan James]

command /?

and

cmd /?

are pretty good. The big thing to notice is one is a "MS-DOS command interpreter" and the other is a "Windows NT command interpreter".

[Tony Morris]

http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html