Trying to catch thread errors

[yelllow4u]

I using StreamGobbler to execute a command line system call. The class seems to work just fine. My problem is that when I try to catch my errors it always comes back "null". Basically I have 3 text boxes that need to be filled in and then the user hits the execute button to run the command. If I mistype something in the first two text boxes (txt_server and txt_server2) teh error that gets returned is "null". If I mistype something in the 3rd text box (txt_VOBStore) I get a usefull error that pops up...which is what I would expect. Below is the code for my main class and my StreamGobbler class. Please take a look over the code and let me know where I might be going wrong...

Code:

     String Error = "";
        
     Process p = null;
     try {
            p = Runtime.getRuntime().exec(command);
            
            // any output?
            StreamGobbler outputGobbler = new
               StreamGobbler(p.getInputStream(), "OUTPUT");
            
            StreamGobbler errorGobbler = new
               StreamGobbler(p.getErrorStream(), "ERROR");
                
            // kick them off
            outputGobbler.run();
            errorGobbler.run();
            Error = errorGobbler.Error;
            
            int returnVal = p.waitFor();
            
            if (returnVal != 0) {
                throw ( new Throwable());
               }
            } catch (Exception e){
               JOptionPane.showMessageDialog(null,
              "Could not change file protections: " + e.getMessage(), "Error", JOptionPane.WARNING_MESSAGE);
              return;
           } catch (Throwable T){
               if (Error != null){
                 JOptionPane.showMessageDialog(null,
                 "Could not change file protections: " + Error, "Error", JOptionPane.WARNING_MESSAGE);
                 return; 
               }else
                   JOptionPane.showMessageDialog(null,
                 "Could not change file protections: " + T.getMessage(), "Error", JOptionPane.WARNING_MESSAGE);
                 return; 
           }

Here is my SG Class...

Code:

import java.io.InputStream;
import java.util.*; 
import java.io.*; 
import javax.swing.JOptionPane;

/*
 * streamGobbler.java
 *
 * Created on August 2, 2007, 1:32 PM
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

/**
 *
 * @author br
 */
public class StreamGobbler extends Thread {
     InputStream is; 
     String type;
     String Error = "";
    /** Creates a new instance of streamGobbler */
    public StreamGobbler(InputStream is, String type) {
        this.is = is;
        this.type = type;
    }
   public void run(){ 
        try
        {
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String line=null;
            while ( (line = br.readLine()) != null)
                      Error = br.readLine();
                    // System.out.println(Error);
            } catch (IOException ex)
              {
               JOptionPane.showMessageDialog(null,
              "Could not change VOB protections: " + ex.getMessage(), "Error", JOptionPane.WARNING_MESSAGE);
              return; 
            } 
      }
}

[henry_78]

Hi,
When u create a new process if u want to know the errors u have to get a reference to the errorStream of that process(which is not your standard input and standard output). Try this code:

InpueStream err = p.getErrorStream();
BufferedReader br = new BufferedReader(new InputStreamReader(err));
try {
String line = br.readline();
while(line != null) {
System.out.println(line);
line = br.readline();
}
}
catch(IOException e) {
}

[yelllow4u]

That makes sense. It also works now. Sometimes I write so much junk I lose track of what is actually happening. I appreciate the help.