JAVA process hang when expectts error stream from C++ application

Thu, 20 Sep 2007 06:10:32 -0000
Hi friends,

My JAVA program has to call c++ (kkk) application and JAVA opens 2
threads to read outputstream and errorstream from c++ application.
See the code below). Since errorstream is expecting some data it hangs
unless c++ feeds the same.
When I used alternative 'perror("")'/'perror(NULL)' in kkk.c hang gets
solved but c++ standalone program keeps throwing dummy error on
Could anybody help me here how it can be rectified.
Thanks in advance
- Krish

public class start
    public static void main(String [] args) throws
        String cmd = "/home/user/kkk";
        Process process = Runtime.getRuntime().exec(cmd);
        MyReader outReader = new MyReader(process.getInputStream());
        Thread outThread = new Thread(outReader);
        MyReader errReader = new MyReader(process.getErrorStream());
        Thread errThread = new Thread(errReader);
        System.out.println("exit code is " + process.waitFor());
        // process.getInputStream().close();
        // process.getErrorStream().close();
        System.out.println("joins completed");

/***** *******/

public class MyReader implements Runnable
    private final InputStream is;
    public MyReader(InputStream is)
    { = is;
    public void run()
        // normally would read in while here, but these threads never get
        // they are blocked on the first read() call forever.
        int length;
           length =;
           if (length == -1)
           if (length == 0)
           System.out.println("read something");
        } catch (Throwable t) {

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
# include <sys/wait.h>

int main()
        perror ("");
// perror (NULL);
        return 0;

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