Name: joT67522 Date: 08/20/97


This is a copy of the code fragment that creates the process
and executes the printit shell script...
================================================================================
=======
      try {
        Runtime rt = Runtime.getRuntime();
        Process pro = rt.exec("/export/home/usr/msgoldst/printit test.dat");
        DataInputStream in =
          new DataInputStream ( new BufferedInputStream(pro.getInputStream()));
        while ((s=in.readLine()) != null) {
           System.out.println("out - > " + s);
        }
        DataInputStream ine =
          new DataInputStream ( new BufferedInputStream(pro.getErrorStream()));
        while ((s=in.readLine()) != null) {
            System.out.println("err - > " + s);
        }
      }
      //.
      //. catch blocks follow for IOException and Exception ...
      //.
================================================================================
====
This is a copy of the shell script that is called printit
================================================================================
====
#!/bin/ksh
lp -dit_printer $1
exit
================================================================================
====
Here is what the process table looks like after running the program ...
Note process pid=24775. Every time the program runs I get a new
<defunct> process.
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====
msgoldst 24775 24769 0 0:00 <defunct>
msgoldst 24349 24347 0 08:10:12 pts/1 0:02 -ksh
msgoldst 24781 24349 1 09:41:02 pts/1 0:00 grep gold
msgoldst 24769 24753 14 09:40:47 pts/2 0:05 /export/home/usr/msgoldst/jdk1.1/
bin/../bin/sparc/green_threads/java -Dorbixweb
msgoldst 24753 24544 1 09:40:28 pts/2 0:00 orbixd
msgoldst 24544 24542 0 08:36:08 pts/2 0:01 -ksh

================================================================================
====
What Can I do about cleaning up the process so that there is no <defunct>
processes ?
Also note that I also experience that the program will hang up on occassion
while
handling the reading of standard input from the child process.

I did discover the following on your fixed bugs for vesion 1.1.2 important known
bugs in the Virtual machine :

bug id Summary:
-------
--------------------------------------------------------------------------------
---------------------------------
1237893 On Solaris platforms only, a blocking read of System.in blocks all
threads. As a crude workaround, call the
          following readin() routine instead of System.in.read(): static int
readin() throws IOException,
          InterruptedException It polls every 50 milliseconds, and it can't
detect EOF, so its behavior is substandard, but
          it works

I wonder if this is what is causing my problem on the process hanging on reading
standard in ? I will try the suggested work-around for this problem but I don't
know what to do about the <defunct> process problem ?
================================================================================
====

Thanks in advance,

Best Regards,

Mark Goldston
###@###.###
Rockwell Automotive
 
company - Rockwell Authomotive , email - ###@###.###
======================================================================


1) create dummy long-lived app

public class Bar {

  public static void main(String args[])
  {
    // Just sit here.
    Object foo = new Object();
    synchronized (foo) {
      try {
foo.wait();
      } catch (InterruptedException e) {}
    }
  }
}

2) create a script that runs the long-lived app.

-rwxrwxr-x 1 abartle 19 Dec 26 12:34 runjava*
#!/bin/sh
java Bar

3) create a Foo class that demonstrates the bug:
Process.destroy won't kill a shell script

import java.io.IOException;
/**
 * Blah
 */
public class Foo {

  public static void main(String args[])
  {
    try
      {
Process foo = Runtime.getRuntime().exec("runjava");
System.out.println("Started runjava");

// Wait 10 seconds
Thread.currentThread().sleep(10000);

// try to kill the process
System.out.println("Killing runjava");
foo.destroy(); // doesn't work

// get exit value -- will throw exception if process not killed!
foo.exitValue();
      }
    catch (InterruptedException e) {System.out.println(e.getMessage());}
    catch (IOException e) {System.out.println(e.getMessage());}
    catch (IllegalThreadStateException e) {System.out.println(e.getMessage());}
  }
}


4) Look at the output of running Foo
foomachine:% java Foo
Started runjava
Killing runjava
process hasn't exited

(it threw the IllegalThreadStateException)

5) Verify that the Solaris process are all still running
 19073 pts/16 S 0:00 /usr/local/java/bin/../bin/sparc/green_threads/java Foo
 19078 pts/16 S 0:00 /bin/sh ./runjava
 19079 pts/16 S 0:00 /usr/local/java/bin/../bin/sparc/green_threads/java Bar

Note BOTH the "runjava" and java Bar are still there!

Thanks for your help,

Aron