System.exit() capture using bat or shell script

[Kumar Jaya]

Hello,

I am having a simple jar file helloworld.jar with a main class helloworld.class which has one statement System.exit(1). I am calling this jar file using java -jar helloworld.jar command. I am using a bat file in windows to execute the above command. Is there a way to capture the value 1 that is been returned by System.exit(1) method. I want to do that in linux shell script also. Thanks in advance.

Regards
Jaya

[Vikash Ananda]

Hi Jaya,

System.exit(value) does not return the value to OS (batch file or shellscript) but it returns to JVM which JVM uses to see if the program was terminated correctly or not. Read Java specifications for the same. Why do you want this value??

Thanks and Regards,
Vikash Anand.

[K. Tsang]

Umm the "integer" in System.exit(int) indicates whether the exit completes successfully (a zero) or with some error (not a zero eg 1). So I doubt you can print the non-zero value.

However if you have exceptions caught you can use the System.err.println() to print out the errors.

[Henry Wong]

Vikash Ananda wrote:
System.exit(value) does not return the value to OS (batch file or shellscript) but it returns to JVM which JVM uses to see if the program was terminated correctly or not. Read Java specifications for the same. Why do you want this value??

Actually, this "value" does eventually get back to the OS (batch file and shellscript). With the batch file, it gets back as the error level, which can be used by the batch to act accordingly. With shellscripts, this value becomes the exit status of the application. And how the shellscripts accesses it depends on the shell being used.

Henry

[Kumar Jaya]

Hi Vikash,

I want that value in my bat/script file to make decisions to display to the user. Is there any way in my bat/sript file where I can trap the values returned by a java program??

Regards
Jaya

[Vikash Ananda]

Hi,

I do not know how to capture that in a batch script but using another program you can do the same: Try code below:

  
import java.util.*;
import java.io.*;
class StreamGobbler extends Thread
{
    InputStream is;
    String type;
    
    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)
                System.out.println(type + ">" + line);    
            } catch (IOException ioe)
              {
                ioe.printStackTrace();  
              }
    }
}
 public static void main(String args[])
    {
       
String osName = System.getProperty("os.name" );
            System.out.println(osName);
            String[] cmd = new String[3];
            if( osName.equals( "Windows NT" ) )
            {
                cmd[0] = "cmd.exe" ;
                cmd[1] = "/C" ;
                cmd[2] = "C:/apache-tomcat-5.5.27/bin/startup.bat";
            }
            else if( osName.equals( "Windows 95" ) )
            {
                cmd[0] = "command.com" ;
                cmd[1] = "/C" ;
                cmd[2] = "C:/apache-tomcat-5.5.27/bin/startup.bat";
            }
            else if( osName.equals( "Windows XP" ) )
            {
                cmd[0] = "cmd.exe" ;
                cmd[1] = "/C" ;
                cmd[2] = "C:/apache-tomcat-5.5.27/bin/startup.bat";
            }
            
            Runtime rt = Runtime.getRuntime();
            System.out.println("Execing " + cmd[0] + " " + cmd[1] 
                               + " " + cmd[2]);
            Process proc = rt.exec(cmd);
            // any error message?
            StreamGobbler errorGobbler = new 
                StreamGobbler(proc.getErrorStream(), "ERROR");            
            
            // any output?
            StreamGobbler outputGobbler = new 
                StreamGobbler(proc.getInputStream(), "OUTPUT");
                
            // kick them off
            errorGobbler.start();
            outputGobbler.start();
                                    
            // any error???
            int exitVal = proc.waitFor();
            System.out.println("ExitValue: " + exitVal);   
           
        } catch (Throwable t)
          {
            t.printStackTrace();
          }  
}

The line int exitVal = proc.waitFor(); will give the process exit value.

Try it and let us know. Is this what you were looking at??

[Vikash Ananda]

Henry Wong wrote:

Vikash Ananda wrote:
System.exit(value) does not return the value to OS (batch file or shellscript) but it returns to JVM which JVM uses to see if the program was terminated correctly or not. Read Java specifications for the same. Why do you want this value??

Actually, this "value" does eventually get back to the OS (batch file and shellscript). With the batch file, it gets back as the error level, which can be used by the batch to act accordingly. With shellscripts, this value becomes the exit status of the application. And how the shellscripts accesses it depends on the shell being used.

Henry

Hi Henry,

Thanks for the info.

[Kumar Jaya]

Hi Vikash,

Yes, but I cant afford to write a java code, but I got it through Henry's words. I got the exit value using the bat/script commands. Thanks for the information Vikash.

Henry,

Thanks for the information..

Regards
Kumaravel J

[Amol Talap]

Kumaravel J : May I know the fix you made. I am struggling for the same as my tracking process in shell script looks for the return/exit status.

[Kumar Jaya]

Hi Amol,

Try this in your script file, I assume that the jar file you want to run is sample.jar

java -jar sample.jar
RETURN=$?


Now the RETURN has the value of the executed command

Regards
Kumaravel J

[Campbell Ritchie]

Too difficult for "beginning Java". Moving thread.