Runtime.exec on Linux

Hi,
I'm having some difficulty getting Runtime.exe() to work on Linux. I was trying to run "make oldconfig" from my Java program.
public Action()
   Process p = Runtime.getRuntime().exec ( "make oldconfig" );
   InputStream processStream = p.getInputStream();
   OutputStream commandStream = p.getOutputStream();
   InputStream procErrorStream = [/getErrorStream();
   p.waitFor ();
private void outputData ()
   int hasInput;
   if ( ( hasInput = processStream.available() ) >0 )
      byte[] buffer = new byte [hasInput];
      int len = processStream.read(buffer);
      if ( len > 0 )
         System.out.println( new String ( buffer, 0, len ) );
   if ( ( hasInput = procErrorStream.available() ) >0 )
      byte[] buffer = new byte [hasInput];
      int len = procErrorStream.read(buffer);
      if ( len > 0 )
         System.out.println( new String ( buffer, 0, len ) );
}I don't see any errors from this command, but it doesn't look like the "make oldconfig" is called because I'm not seeing any outputs. Can anyone help or give me some hints to debug this? Thanks.

The line
InputStream procErrorStream = [/getErrorStream();
looks a bit dodgy to me

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How to make Runtime.exec call Linux exec?

Howdy,
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rm -rf *
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Bob

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Runtime.exec() under Linux

My game's installer works on windows and mac but on linux it's getting this error:
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at java.lang.Runtime.exec(Unknown Source)
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Have you tried including the full path for javaw in
the Linux version?It is interesting to note that the Linux version does not have a javaw

Runtime.exec() on Linux RedHat. help!!

Guys
I've having a lot of problems with Runtime.exec() across RedHat platforms.
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when I execute the 'ps' sentence the process appears, but apparently don't work.
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Don't forget that the output of the "Process" is not redirected to "System.out".
--> if you want to see the output, you'll have to get the output stream of the process and dump it yourself
InputStream processOutput = process.getOutputStream() ;
byte buffer[] = new byte[ 512 ] ;
while( true ) {
int read = processOutput.read( buffer ) ;
if( read<=0 ) {
break ;
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Runtime exec undel linux

Hi
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Have you tried including the full path for javaw in
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Performance issue Runtime. exec("cp folder1 folder") in Linux,Weblogic.

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A 64 bit VM is not necessarily faster than a 32 bit one. I remember at least on suggestion that it could be slower.
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Runtime.exec() does not work under Linux

Hi,
I have a generic application runner class that runs an external
program and redirects stdout/stderr to a buffer/file.
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'java':
java.io.IOException: "/usr/lib/SunJava2-1.3.1/jre/bin/java": not found
at java.lang.UNIXProcess.forkAndExec(Native Method)
at java.lang.UNIXProcess.<init>(UNIXProcess.java:139)
at java.lang.Runtime.execInternal(Native Method)
at java.lang.Runtime.exec(Runtime.java:546)
at java.lang.Runtime.exec(Runtime.java:413)
I have checked that the file /usr/lib/SunJava2-1.3.1/jre/bin/java
exists.
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can I ask how you solved it? I am having a problem
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only used quotes under Windows.
Marc

Runtime.exec(), linux and redirection

Hi all,
I need to exec an external command from java under linux, and have both the stderr and stdout of the command redirected to the
stdout, so that I can capture them and keep them in synch in the java app. I've tried many combination, but I'm unable to make
this work: only the standard output shows up. Note that I can make this work under windows.
A java code example and a small C example to simulate the program to be invoked follows. Running the java program should show both the "messsage" and the "error" lines, but it shows only the "message" ones.
Note that removing the apparently redoundant ">&1" doesn't solve the problem. I got a suggestion to modify the exec invocation into
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Roberto
======================= class test.java ================================================
import java.io.*;
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======================= test1 program ================================================
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int i;
for(i=0; i<100; i++) {
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}======================= end of test1 program ================================================

Redirection dosen't work with Runtime.exec(), it really dosen't have sense. Do the foolowing:
String[] cmd = { "/bin/sh", "-c", "./test1" };
Process p = Runtime.getRuntime().exec(cmd);
OutputStream out = p.getOutputStream();
//now wrte out to the file, formating as you want
What is doene obove is execute your command, without redirection, and the obtaininh the output stream of the created process. This is "the place" where the process will write everithig it'll would write in the console if executed there.
The handle the OutputStream as any other OutputStream, and write it to the HD or do whtever you want.
Abraham.

Problem of executing a process under Linux using Runtime.exec

Hi, All
I am having a problem of executing a process under Linux and looking for help.
I have a simple C program, which just opens a listening port, accept connection request and receive data. What I did is:
1. I create a script to start this C program
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I can see this C program is started, and it is doing what it supposed to do, opening a listening port, accepting connection request from client and receiving data from client. But if I stop the Java application, then this C program will die when any incoming data or connection request happens. There is nothing wrong with the C program and the script, because if I manually execute this script, everying works fine.
I am using jre1.4.2_07 and running under Linux fedora 3.0.
Then I tried similar thing under Windows XP with service pack2, evrything works OK, the C program doesn't die at all.

Mind reading is not an exact science but I bet that you are not processing either the process stdout or the stderr stream properly. Have you read http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html ?

Runtime.exec() on RedHat Linux

Guys
Like many before me, it seems, I've having a nightmare with Runtime.exec() across platforms when executing local files.
I've gone for the basic but robust strategy of writing the required function to a local file and then executing the file. This has worked fine on Windows NT/2000 and on Solaris. But RedHat Linux doesn't want to know.
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An old chestnut, I know. But can anyone offer an help?
Cheers
Dom

Here's a small class & main method that illustrates the problem.
The output I get is:
File path: /tmp/Temp26345.sh
chmod +x exit value: 0
Executing file: 255
I can then go into /tmp and run ./Temp26345.sh at the command line and get the "ls" command to run.
import java.io.*;
public class FileExecutor
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               fe.executeFile( executable );
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               t.printStackTrace();
     public File createFile( String fileName , String contents )
          throws IOException
          //Create the file.
          File tempFile = File.createTempFile( fileName , ".sh" );
          //Write to the file.
          FileOutputStream fos = new FileOutputStream( tempFile );
          OutputStreamWriter osw = new OutputStreamWriter( fos, "UTF-8" );
          int length = contents.length();
          osw.write( contents , 0 , length );
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          Process process_exec = runtime.exec( filePath );
          exitValue = process_exec.waitFor();
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Runtime.exec() problem with Linux

Hi All,
I have a java program which I am using to launch java programs on all platforms.
I am using the Runtime.exec() method to start the process in a separate JVM.
But, I had a problem with the -classpath switch if the directories contained spaces. So I modified the java command which I am passing to the exec() method to something like:
java -classpath \"./my dir with spaces\" com.harshal.MainThis I had to do because of the problem in windows. But, if I use double quotes in Linux (for the classpath switch in my exec() method), it won't work.
Can anyone correct me so that I can use the Runtime.exec() method on all platforms to launch the java application even if the classpath directories contains spaces.
Thank you very much.

I was reading about the command line args on java's
tutorial and I found a shocking news. Mac OS doesn't
support command line args, That's news to me. Could you please elaborate ?
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Ran a new test, got it working.
Sample:
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String[] envp = new String[]{
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How to capture output of java files using Runtime.exec

Hi guys,
I'm trying to capture output of java files using Runtime.exec but I don't know how. I keep receiving error message "java.lang.NoClassDefFoundError:" but I don't know how to :(
import java.io.*;
public class CmdExec {
public CmdExec() {
public static void main(String argv[]){
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     //BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
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     while ((line = input.readLine()) != null) {
        System.out.println(line);
     input.close();
    catch (Exception err) {
     err.printStackTrace();
public class E {
    public static void main(String[] args) {
        System.out.println("hello world!!!!");
}Please help :)

Javapedia: Classpath
How Classes are Found
Setting the class path (Windows)
Setting the class path (Solaris/Linux)
Understanding the Java ClassLoader
java -cp .;<any other directories or jars> YourClassNameYou get a NoClassDefFoundError message because the JVM (Java Virtual Machine) can't find your class. The way to remedy this is to ensure that your class is included in the classpath. The example assumes that you are in the same directory as the class you're trying to run.
javac -classpath .;<any additional jar files or directories> YourClassName.javaYou get a "cannot resolve symbol" message because the compiler can't find your class. The way to remedy this is to ensure that your class is included in the classpath. The example assumes that you are in the same directory as the class you're trying to run.

Runtime.exec - Too Many Open Files

System version : Red Hat Enterprise Linux 2.4.21-47.ELsmp AS release 3 (Taroon Update 8)
JRE version : 1.6.0-b105
Important : the commands described below are launched from a Web application : Apache Tomcat 6.0.10
Hello,
I'm facing a problem already known, but appearantly never really solved ??!! ;)
When I invoke many system commands with the 'Runtime.exec(...)' method, there are open files that are not released (I can see them with the "lsof" system command) .
At the end, the unavoidable "too many open files" Exception.
The lauched commands are "ssh ... " commands.
In the topics relating to this problem, the solution is always to close all Streams / threads and to explicitely invoke the method "Process.destroy()".
My problem is that this is what I do ! And I can't do more...
Here is the code :
       Runtime rt = Runtime.getRuntime();
       Process process = rt.exec("ssh ...");
        // ProcessStreamHolder extends Thread and reads from the InputStream given in constructor...
        ProcessStreamHolder errorStream = new ProcessStreamHolder(process.getErrorStream());
        ProcessStreamHolder outputStream = new ProcessStreamHolder(process.getInputStream());
        errorStream.start();
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            logger.warn("...");
        try {
            process.getOutputStream().close();
        } catch (RuntimeException e) {
            logger.warn("...");
        try {
            process.getErrorStream().close();
        } catch (RuntimeException e) {
            logger.warn("...");
        process.destroy();Does someone know if my code is wrong or if there's a workaround for me ?
Thanks by advance !
Richard.

Don't interrupt those threads. Close the output stream first, then wait for the process to exit, then both threads reading the stdout and stderr of the process should get EOFs, so they should exit naturally, and incidentally close the streams themselves.

Runtime exec problem to execute a C program

Hi,
I've spend lot of time trying to find a solution without success...
My aim is to run a C program from a java application under linux. My C code is the following:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
main(int argc, char **argv){
printf("hello world \n");
Once compiled I run my java application wich run the binary through a runtime.exec().
I followed the example given by
http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html
with the same input gobblers and threads.
For some reason it doesn't work: nothing comes out...
When I call "ls" instead of my binary it works perfectly!
WHY??
Any help would be greatly appreciated!

Thanks for the reply.
Yes it seems that JNI could be a solution, but it looks a bit complicated an maybe not so well adapted to my purpose.
The executables I want to execute from my java application don't need any arguments.
If JNI is really the only way I'll try to use it but is there any good reason why runtime exec doesn't work? It is supposed to execute any executable isn't it?
cheers

Using runtime.exec to zip some files

Hi,
I am using runtime.exec to try to automatically zip a bunch of files on a server. However, it does not seem to be working.
Before I execute the command, I save the zip command in a string. I then print the string to a log file, and then execute the runtime zip command. But nothing happens.
Yet, when I copy the string from the log, and paste it in a terminal, it properly creates the zip files. So, I know I have the correct command string, it just does not seem to be working within the java application. Also, the command string uses fully qualified directories, so it is not a directory issue.
I am using ubuntu linux.
Any ideas?
-Adam

adamSpline wrote:
Hi,
I am using runtime.exec to try to automatically zip a bunch of files on a server. However, it does not seem to be working.
Before I execute the command, I save the zip command in a string. I then print the string to a log file, and then execute the runtime zip command. But nothing happens. Within Runtime.exec() any command does not run in a shell and I bet you use wild cards and/or other commands to be interpreted by a shell which will not be interpreted since there is no shell. And, since you don't mention error messages or the return code, I will also bet you don't process the Process stdout , stderr and the return code properly.
It looks to me like you have fallen for at least two for the traps in [http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html|http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html].
>
Yet, when I copy the string from the log, and paste it in a terminal, it properly creates the zip files. So, I know I have the correct command string, it just does not seem to be working within the java application. Also, the command string uses fully qualified directories, so it is not a directory issue.
I am using ubuntu linux.
Any ideas?I agree with 'masijade' - use the built in Java classes.
>
-Adam

Runtime.exec on Linux

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