Re: exec problem is JDK 1.7.0_21

On Sun, 21 Apr 2013 19:47:39 +0000, Martin Gregorie wrote:


This niggled me, so here's a replacement for 'testscript' which *does*
honour quoted command line arguments:

$ cat testscript
#!/bin/bash
i=0
echo "$# arguments"
for f in "$@"
do
  echo "arg[$i]=$f"
  i=$(expr $i + 1)
done
exit $i
$

Tested and shown to work in my version of the SSCE:

$ java TestProcessBuilder testscript a cat and "a mouse in its hole"
4 arguments
arg[0]=a
arg[1]=cat
arg[2]=and
arg[3]=a mouse in its hole
exitValue=4
$

The fix was changing echo ' for f in $* ' to ' for f in "$@" '.

For completeness, here's my version of the ProcessBuilder SSCE. As well
as grabbing the ProcessBuilder constructor arguments from the command
line, I made Exception trapping explicit so where they're issued is
unambiguous and made the Runnable class into a named class:

import java.io.*;
public class TestProcessBuilder
{
   public static void main(String[] args) throws Exception
   {
      try
      {
         ProcessBuilder pb = new ProcessBuilder(args);
         pb.redirectErrorStream(true);
         Process p = pb.start();
         Thread t = new Thread(new TestRunnable(p.getInputStream()));
         t.start();
         t.join();
         print("exitValue=%d", p.exitValue());
      }
      catch(NullPointerException e)
      {
         print("ProcessBuilder.start() threw NullPointerException %s",
               e.getMessage());
      }
      catch(IndexOutOfBoundsException e)
      {
         print("ProcessBuilder.start() threw IndexOutBoundsException %s",
               e.getMessage());
      }
      catch(IOException e)
      {
         print("ProcessBuilder.start() threw IOException %s",
               e.getMessage());
      }
   }

   private static void print(String format, String value)
   {
      System.out.println(String.format(format, value));
   }

   private static void print(String format, int value)
   {
      System.out.println(String.format(format, value));
   }
}

import java.io.*;
public class TestRunnable implements Runnable
{
   private InputStream is;
   
   public TestRunnable(InputStream is)
   {
      this.is = is;
   }
   
   public void run()
   {
      int n;
      try
      {
         while ((n = is.read()) != -1)
            System.out.print((char)n);
      }
      catch (IOException ioe)
      {
         System.out.println("IOException in TestRunnable");
         ioe.printStackTrace();
      }
   }
}

--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |