Runtime.execute("Some batch file")

Posted on 2004-09-01
Medium Priority
Last Modified: 2007-12-19
To conform with Sarbanes-Oxley, I am writing a Java program that will allow a user to login to an intranet site and request a password for an "Emergeny login Profile" on an AS400.

My code verifies that the user is authorized to access this profile and then changes the password for that profile and divulges it to the user.

I am having problems when executing the call that changes the password.

//code snippet (in a servlet)
    // generate a random 10 charcter password (first must be alphabetic, rest are alphameric)
    profile.switchPassword(userBean.getUserName(), Integer.parseInt(duration), reason);
    // Now actually switch it on the AS400
    Runtime run = Runtime.getRuntime();
    String[] commandLine = {"C:\\WINNT\\rmtcmd.exe","chgusrprf", profile.getProfileName(), profile.getPassword()};

    Process proc = run.exec(commandLine);
    int exitCode = proc.waitFor();
    if (exitCode != 0){
        throw new Exception("Error changing password on AS/400. Error Code: " + exitCode);

--Batch file contents..
RMTCMD chgusrprf %1 %2
-- End of Batch File Contents

I have the connection properties set up in AS400 Operations to use a default user and prompt for password when necessary.
I have the same user set up on the windows server with the same password.

When I execute the commandline from either the RUN prompt in window, or in a DOS environment, it works fine.
When called via the java code, the password gets changed successfully, but the code seems to hang at the call to proc.waitFor().

After reading the documentation,it is my understanding that the servlet thread waits until the call to the batch file finishes.  The batch file obviously finished because the password got changed.

I need a way of knowing that the call "RMTCMD chgusrprf profilename password" was successful before I divulge the password to the user.

If more info is needed, please let me know.

Any help would be appreciated.

Question by:beermequik
  • 2
LVL 35

Accepted Solution

TimYates earned 1000 total points
ID: 11953229
It is probably waiting for you to read some output form it...

class StreamGobbler extends Thread
    InputStream is;
    String type;

    StreamGobbler(InputStream is, String type)
        this.is = is;
        this.type = type;

    public void run()
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String line=null;
            while ( (line = br.readLine()) != null)
               System.out.println( type + ">" + line ) ;
            } catch (IOException ioe)


    Process proc = run.exec(commandLine);
    StreamGobbler errorGobbler = new StreamGobbler(proc.getErrorStream(), "ERROR");
     // any output?
    StreamGobbler outputGobbler = new StreamGobbler(proc.getInputStream(), "OUTPUT");
    // kick them off
    // any error???
    int exitCode = proc.waitFor();
    if (exitCode != 0){
        throw new Exception("Error changing password on AS/400. Error Code: " + exitCode);
LVL 13

Expert Comment

ID: 11953320
another possible idea is to create a CL with this command in it (CHGUSRPRF) passing in the necessary parms. After the statement has been executed, send back a return value to your program. Enter the CL as a stored procedure.


Author Comment

ID: 11953472
That did it!  Thanks

I was trying to read the output streams at one time, but was unsuccessful (I never used Streams outside of files)
Thanks for the code snippet too.
LVL 35

Expert Comment

ID: 11953496
Glad I could help :-)

Good luck with it!!


Featured Post

The 14th Annual Expert Award Winners

The results are in! Meet the top members of our 2017 Expert Awards. Congratulations to all who qualified!

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

INTRODUCTION Working with files is a moderately common task in Java.  For most projects hard coding the file names, using parameters in configuration files, or using command-line arguments is sufficient.   However, when your application has vi…
Java functions are among the best things for programmers to work with as Java sites can be very easy to read and prepare. Java especially simplifies many processes in the coding industry as it helps integrate many forms of technology and different d…
This tutorial covers a step-by-step guide to install VisualVM launcher in eclipse.
This video teaches viewers about errors in exception handling.
Suggested Courses

627 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question