Java.lang.Runtime.exec() again

try{
Process registryProcess = null;
Runtime r = Runtime.getRuntime();
String[] cmdArray = {"F:\\windump", ">>new_res.txt"};
registryProcess = r.exec(cmdArray);
}catch(Exception ex){
System.out.println("Exception Caught: " + ex.getMessage());
** Have also tried speicfying the command and the parameters all in the one string like so :
String cmd = "F:\\windump >>F:\\new_res.txt";
registryProcess = r.exec(cmd);

try
String cmd = "cmd /c F:\\windump >> F:\\new_res.txt";
registryProcess = r.exec(cmd);

Similar Messages

Java.lang.Runtime.exec problem in ubuntu 9.10

Hi:
I tried to run some command in the java code , for example "grass64 -text /home/data/location", this command works well in the terminal, however when I call it in the java code I got some excepetions.
My code is :
public class Grass {
     public static String grassBatJob="GRASS_BATCH_JOB";
     public void run(String cmd,String jobPath) {
          //set the environments variables
          Map<String, String> env=new HashMap<String, String>();
          env.put(grassBatJob, jobPath);
          String gisDataBase="/home/kk/grass/GrassDataBase";
          String location="spearfish60";
          String mapset="PERMANENT";
          cmd=cmd+" "+gisDataBase+"/"+location+"/"+mapset;
          CommandLine line=new CommandLine(cmd);
          //the real cmd should be >>grass64 -text /home/kk/grass/GrassDataBase/spearfish60/PERMANENT
          System.out.println("start line=="+line.toString());
          DefaultExecutor de=new DefaultExecutor();
          try {
               int index=de.execute(line,env);
               System.out.println(index);
          } catch (ExecuteException e) {
               e.printStackTrace();
          } catch (IOException e) {
               e.printStackTrace();
     public static void main(String[] args) {
          String jobPath=Grass.class.getResource("grass.sh").getFile();
          new Grass().run("grass64 -text", jobPath);
The real cmd I want to execute is "grass64 -text /home/kk/grass/GrassDataBase/spearfish60/PERMANENT" with the envrionment variable "GRASS_BATCH_JOB=jobPath",it works well in the ternimal ,however in my application I got the exception"
java.io.IOException: Cannot run program "grass64 -text /home/kk/grass/GrassDataBase/spearfish60/PERMANENT": java.io.IOException: error=2, No such file or directory
     at java.lang.ProcessBuilder.start(ProcessBuilder.java:459)
     at java.lang.Runtime.exec(Runtime.java:593)
     at org.apache.commons.exec.launcher.Java13CommandLauncher.exec(Java13CommandLauncher.java:58)
     at org.apache.commons.exec.DefaultExecutor.launch(DefaultExecutor.java:246)
     at org.apache.commons.exec.DefaultExecutor.executeInternal(DefaultExecutor.java:302)
     at org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:149)
     at org.kingxip.Grass.run(Grass.java:27)
     at org.kingxip.Grass.main(Grass.java:38)
Caused by: java.io.IOException: java.io.IOException: error=2, No such file or directory
     at java.lang.UNIXProcess.<init>(UNIXProcess.java:148)
     at java.lang.ProcessImpl.start(ProcessImpl.java:65)
     at java.lang.ProcessBuilder.start(ProcessBuilder.java:452)
     ... 7 more
I wonder why?

Thanks for all of your reply, and now I can run the command, however I met some problems when I tried to get the result of the exec.
The core codes are shown below:
String cmd="g.version";
String[] exe={"bash","-c",cmd};
Process p1=Runtime.getRuntime.exec(exe,env); // the env has been set
GrassThread outThread=new GrassThread("out", p1.getInputStream());
outThread.start();
GrassThread errorThread=new GrassThread("error", p1.getErrorStream());
errorThread.start();
int exitVal = p1.waitFor();
String resu=outThread.sb.toString();
System.out.println("==========the output start========");
System.out.println(resu);
System.out.println("==========the output end========");
System.out.println("ExitValue: " + exitVal); //------------------> line one
public class GrassThread extends Thread{
     public StringBuffer sb=new StringBuffer();
     public GrassThread(String type,InputStream is) {
          this.type=type;
          this.is=is;
     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);
                    sb.append(line).append("\r"); // ----------------------------> line two
}I define a StringBuffer in the GrassThread to save the output (see the code where I marked by "line two"), and when the process complete, I check the StringBuffer to get the output (see code where I marked by "line one"), however the output in the console of the IDE are :
----------- output in the console of the IDE start -------------
==========the output start========
==========the output end========
ExitValue: 0
out>GRASS 6.4.0RC5 (2009)
----------output in the console of the IDE end--------------------
I can not understand, in the code "line one", I first get the output using "System.out.println(resu);",then I print the exitvalue,but why the order of the output in the console is not what I expected?
Another question, the code above assume the output can be got from the Process's getInputStream, however sometimes the output maybe come from the Process's getErrorStream, so how to handle it?
Edited by: apachemaven on 2010-3-5 ??5:38

Java.lang.Runtime.exec()

When using the exec method I cannot get it to run the specified application when I try to use the Runtime.execString[] cmdArray)
The application I am running is windump, it runs ok when I specify it in the Runtime.exec(String cmd) method.
I need to use the Runtime.exec(String[] cmdArray) option as I need to specify parameters as part of my project. To be exact I need to tell it to output to a text file.
I can do this when running windump from the command prompt, thus cannot understand whty it wont work when I specify the same option from Runtime.exec(..)
Any ideas how to overcome this?
thanks Conor

This works for me on WindowsNT:
try {
Runtime.getRuntime().exec("cmd.exe /c dir>dirtest.txt");
catch (Exception e) {}
[/code}
Mark

Invoke exe through java code(using java.lang.Runtime)

Iam trying to invoke an exe from java code.If i give the complete path for that exe it is running fine .But if i set the environment variable and directly execute the exe through command prompt it iss running fine , but it fails to run when i do the same using java code i.e. java.lang.Runtime.exec function

Give "//" for directory seperator.
E.g. r.exec("c://test//test.exe",null);
Why? That doesn't look correct.It is correct. It will work fine. Try it out.But it doesn't add or solve anything. A forward slash
does not need to be escaped.'
It's not even escaping. It's just doubling up. If that works, I'd bet "C://///test///////test.exe" does also.

Java.lang.Process.exec()

I have read a article about the "java.lang.Process.exec()" (url:http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html)
Having some questions with the example in it.
The example code:
import java.util.*;
import java.io.*;
public class BadExecJavac
    public static void main(String args[])
        try
            Runtime rt = Runtime.getRuntime();
            Process proc = rt.exec("javac");
            //int exitVal = proc.exitValue();
            int exitVal = proc.waitFor();
            System.out.println("Process exitValue: " + exitVal);
        } catch (Throwable t)
            t.printStackTrace();
}The process can run but never complete.
Why? Just because when invoke the javac.exe without any argument,it will product a set of usage statements that describe how to run the program and the meaning of all the available program options.So the process is in deadlock.
The question is, when i change the exec("javac") to exec("javac a.java"), in which the "a.java" is not exist, so the jvm should product error:
error: cannot read: a.java
1 error
But after i changed the code and run the class, at this time the process can run and complete.
The two codes both product some statements,but why the first one never complete,but the second did. Why?

import java.util.*;
import java.io.*;
public class A
    public static void main(String args[])
        try
            Runtime rt = Runtime.getRuntime();
            Process proc = rt.exec("javac");
            InputStream is = proc.getErrorStream();
            int i=0;
            while ((i = is.read()) != -1)
                System.out.print((char)i);
            // int exitVal = proc.exitValue();
            // int exitVal = proc.waitFor();
            // System.out.println("Process exitValue: " + exitVal);
        } catch (Throwable t)
            t.printStackTrace();
}usng this modification, i could see some error messages.
because exec(cmd) executes the command in a separate process, it will not display the results on the current console. If you want see the results, you should use getInputStream() and getErrorStream().
good luch ^^

Java's Runtime.exec() method

When you shell out to java's Runtime.exec() method, are the process name and arguments the same for the child process that is spawned.
We see duplicated processes about the time when our logs tell us this command was run. However, we cannot seem to reproduce this. Has anyone else seen anyone this before?

That's what I though too. But check this out . . .
Our code looks as follows:
private Runtime rt;
private Process p;
rt = Rutime.getRuntime();
p = rt.exec(command);
This exec() call creates a new process, which is a child of the java process that runs this command. The final process looks like the "command" string that is passed to the exec() method call. In our case, the command is a call to the /usr/bin/mail utility to send out faxes and emails.
We ran a very tight loop executing the rt.exec() call over and over. What we found was that for a minor fraction of a second, the newly created process looks just like the original process including the same arguments. However, the PID's indicated that one process was the child of the other. This is why it looked like we had 2 of the same processes. WILD!
Thanks guys!

Hi java.lang.System.gc() vs java.lang.Runtime.gc()

hi all what is the exact diff.,
java.lang.System.gc() vs java.lang.Runtime.gc()
why dont I call Runtime.gc() like System.gc(), is ther any possibility ?
Thanks in advance

Thanks, but I just want to call Runtime.gc() like
System.gc() forcefully to invoke finalize() method
Thanks in advanceThe calls are the same. Read the javadoc:
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/System.html#gc()
public static void gc()
Runs the garbage collector.
Calling the gc method suggests that the Java Virtual Machine expend effort toward recycling unused objects in order to make the memory they currently occupy available for quick reuse. When control returns from the method call, the Java Virtual Machine has made a best effort to reclaim space from all discarded objects.
The call System.gc() is effectively equivalent to the call:
Runtime.getRuntime().gc()

Invoke RealVNC using java code(java.lang.Runtime)

I would like to invoke vncviewer exe whenever user presses a button.Please help

What part are you having trouble with? What have you done so far?
Note that you have two main problems to solve here.
Do you know how to perform a given action when a button is pressed? If not, google for a swing tutorial. You'll want some kind of Listener, though I don't know the specific class name.
Do you know how to invoke another executable program from within a Java app? If not, look into Runtime.exec.

Java/lang/Runtime exception

java.lang.RuntimeException: IOException reading reader invalid byte 1110011 error caused while running sun Wireless tool kit.Can any body please help me to solve this problem. I am using Eclipse 3.3 and also eclipse 3.2
with sun java wireless toolkit in ubuntu.
Thanks and Regards,
Pandian

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Executing a shell script from java using runtime.exec()

Hi I am trying to create a script (test_script) and execute it -- all within one java program...
the code compiles and executes perfectly but nothing happens. This is probably because the script does not get changed to the '777' mode although i am trying to do that ... any suggestions ???
//code
import java.io.*;
import java.util.*;
public class ScriptBuilder
     public ScriptBuilder() {
     public void writeScript() throws java.io.IOException{
     FileWriter writer = new FileWriter(new File("test_script"));
          writer.write("#! /bin/sh\n");
          writer.write("cd prodiags\n");
          writer.write("tar cvf delTask.tar delTask\n");
          writer.write("rm -rf delTask\n");
          writer.flush();
          writer.close();
Runtime rt= Runtime.getRuntime();
String[] cmd = new String[3];
cmd[0] = "ls";
cmd[1] = "chmod 777 test_script";
cmd[2] = "./test_script";
rt.exec(cmd);
     public static void main (String[] args)throws java.io.IOException
     ScriptBuilder sb = new ScriptBuilder();
     sb.writeScript();
}

I don't know exactly but the code written below is working fine try the same with your code .Even with your code instead running the code with
" ./<filename> ",if you execute it with "sh <filename>" command without changing the mode of the file it is executing properly.
import java.io.*;
import java.util.*;
public class ScriptBuilder
public ScriptBuilder()
public void writeScript() throws java.io.IOException
FileWriter writer = new FileWriter(new File("test_script"));
writer.write("#! /bin/sh\n");
writer.write("ll>/home/faiyaz/javaprac/checkll");
writer.flush();
writer.close();
Runtime rt= Runtime.getRuntime();
rt.exec("chmod 777 test_script");
rt.exec("./test_script");
} public static void main (String[] args)throws java.io.IOException
ScriptBuilder sb = new ScriptBuilder();
sb.writeScript();
}

Java.lang.Runtime()

I made a small addition program using 'C'. It accepts 2 no.s and produces the result.
how can i send the 2 no.s to the C program? Here is the code i tried:
Runtime r=Runtime.getRuntime();
Process p=r.exec("add.exe");
InputStream ios=p.getInputStream();
OutputStream ops=p.getOutputStream();
String a="1\n", b="2\n", text;
ops.write(a.getBytes());
ops.write(b.getBytes());
BufferedReader br=new BufferedReader(InputStreamReader(ios));
while ( (text=br.readLine())!=null)
System.out.println(text);I'm neither getting any output nor any error. What do i do? Plz help and thanks in advance.

Maybe this time:
ops.write(a.getBytes());
ops.write(b.getBytes());
ops.flush();
[/code[

I am trying to set up Recipefox to export MasterCook 11. What configurations should be "export" box. I am also getting an error message that Java.lang.Runtime exception. could not create a new folder for the writer.

When Igo to "Export them" a box shows that my configuration paths are not correct.

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Increasing memory used by java process when calling Runtime.exec()

Hi everyone!
I'm running a servlet Oracle iAS 9i, Jserv. It receives an image posted by a user and does a System.exec() which performs a call to convert (an image processing utility included in ImageMagick).
After a few hours, java process start taking more and more RAM, until it crashes with an error like this:
Memory: 5394008 free of 134217728 total. (I log this myself)
Exception: java.io.IOException: Not enough space
java.lang.UNIXProcess.forkAndExec(), line -2.
java.lang.UNIXProcess.<init>(), line 54.
java.lang.Runtime.execInternal(), line -2.
java.lang.Runtime.exec(), line 553.
ImageProcessor.convert(), line 235.
ImageProcessor.createItemPics(), line 124.
Uploader.doPost(), line 69.
As you can see, this is not an OutOfMemoryError, but something else in connection with O/S.
This is not related to hard disk space, since there is a lot of free space in every filesystems
After restarting the webserver, everything goes back to normal and start increasing RAM again.
Is there anything I can do? Any help will be gratly appreciated... Thanks!!!
Dani.-

Have you had any solutions to this pal?
I am also suffering. I tried closing the processes by:
Runtime runtime = Runtime.getRuntime();
Process proc = runtime.exec("/opt/sta_rpms.sh " + sFileName);
proc.waitFor();
proc.getInputStream().close();
proc.getOutputStream().close();
proc.getErrorStream().close();
proc.destroy();
proc = null;
but still after like a day...Though our codes are not alike, it sounds like the same reason.
Cheers!

Why cant I Runtime.exec(file.getAbsolutePath()) ???

I want to run custom file (not directory!) using Runtime.exec() (or you know other way? :) )
Here is what i get::
java.io.IOException: CreateProcess: C:\Documents and Settings\Sugar.SERVER\jbproject\test\theFileICannotOpen.txt error=2
     at java.lang.Win32Process.create(Native Method)
     at java.lang.Win32Process.<init>(Win32Process.java:66)
     at java.lang.Runtime.execInternal(Native Method)
     at java.lang.Runtime.exec(Runtime.java:566)
     at java.lang.Runtime.exec(Runtime.java:428)
     at java.lang.Runtime.exec(Runtime.java:364)
     at java.lang.Runtime.exec(Runtime.java:326)
     at NotWorkingRuntimeClass.main(NotWorkingRuntimeClass.java:27)P.S. 1) the file i want to open EXISTS.
2) I can get also the 193 error code.
P.P.S. It WORKS on *.exe files. How to make all type-files to open? (allow the system to decide which application to use for opening the fie, of course...)
Please help!
THANK YOU!!!

Well, then i've got another question.
How to open the specified file using the system's default program for such file types?
Thanks again, Boris.

Runtime exec IOException issues

Hello,
I have spent two 10 hours days on this problem with countless search permutations and peering into everything from kernel source to java source. Unfortunately, I am not coming up with useful results.
Overview:
I have a very large java application (Apache solr) running on a server with 12GB memory. Without going into too much detail, this application at a point will use a Runtime exec call to fire off a bash shell script. Over time, however, I end up with an IOException "Cannot allocate memory." (More info and stack trace below.)
That application aside I have been able to reproduce this by varying the -Xms and -Xmx jvm parameters with confusing results using the simple program below:
//Use with various -Xms and -Xmx arguments to produce
//IOException on call to Runtime.exec()
import java.io.*;
public class DoRuntime {
   public static void main(String args[]) throws IOException {
      Runtime runtime = Runtime.getRuntime();
      long total = runtime.totalMemory();
      long max = runtime.maxMemory();
      long free = runtime.freeMemory();
      System.out.println("total: " + total);
      System.out.println("max: " + max);
      System.out.println("free: " + free);
      Process process = runtime.exec("/bin/ls");
      InputStream is = process.getInputStream();
      InputStreamReader isr = new InputStreamReader(is);
      BufferedReader br = new BufferedReader(isr);
      String line;
      while ((line = br.readLine()) != null) {
         System.out.println(line);
}Here are some sample runs:
RUN1
rwoodrum@util1wad:~/tmp$ java DoRuntime
total: 188743680
max: 954466304
free: 187759312
DoRuntime.class
DoRuntime.java
rwoodrum@util1wad:~/tmp$
RUN2
rwoodrum@util1wad:~/tmp$ java -Xms10g -Xmx10g DoRuntime
total: 10290069504
max: 10290069504
free: 10236381080
Exception in thread "main" java.io.IOException: java.io.IOException: Cannot allocate memory
        at java.lang.UNIXProcess.<init>(UNIXProcess.java:148)
        at java.lang.ProcessImpl.start(ProcessImpl.java:65)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:451)
        at java.lang.Runtime.exec(Runtime.java:591)
        at java.lang.Runtime.exec(Runtime.java:429)
        at java.lang.Runtime.exec(Runtime.java:326)
        at DoRuntime.main(DoRuntime.java:14)
rwoodrum@util1wad:~/tmp$
RUN3
rwoodrum@util1wad:~/tmp$ java -Xms10g -Xmx11g DoRuntime
total: 10290069504
max: 10498867200
free: 10236381080
DoRuntime.class
DoRuntime.java
rwoodrum@util1wad:~/tmp$-----
(FWIW, I get the same results replacing /bin/ls with something as lightweight as /bin/true.)
As can be seen in the above output of RUN2, I have set a fixed heap size of 10GB. The jvm seems content with that heap size, but when it goes to exec the child process it becomes rather unhappy. From this I would perhaps conclude that ultimately inside the call to forkAndExec (libjava.so) the call to fork() failed with an ENOMEM. (As a side note, an strace on the process doesn't actually ever show a fork, only a call to clone - which utilizes a fork eventually - more on clone below.)
The results of RUN3, however, seem to imply that the problem is within the jvm itself. In RUN3, I set the initial heap allocation to 10GB, as in RUN2, but I set the maximum at 11GB. One would think (or at least I would) that if the fork in RUN2 failed that it would certainly fail in the case of RUN3. It doesn't.
The manpage of clone indicates that the child process will "share parts of its execution context with the calling process". Indeed, if I'm reading it correctly, it indicates that the child process stack (among other things) is housed in the parent process address space.
Could it be that by setting this very large, fixed heap size as in RUN2, there is no room for the jvm to "maneuver" and properly handle the effort of the Runtime.exec? The fact that RUN3 is successful is what has made me think something like this, but I am by far an expert on how the jvm would handle that sort of thing.
In our production setup of this application, I adjusted the Xmx setting to be something larger than the Xms setting. This worked for a period of time, but eventually produced the same results. I suspect over time the heap simply increased toward the max and again the jvm couldn't do its thing when it came time to RunTime.exec. The fact that this happens on the trivial Runtime.exec program would seem to rule out a memory leak of the production application.
Ultimately something fishy is going on with memory, but with seemingly contradictory results, I am at a loss of where the problem lies.
If I have omittied any potentially relevant information, please let me know. Any thoughts are greatly appreciated.
Some basic system information:
rwoodrum@util1wad:~/tmp$ free
             total       used       free     shared    buffers     cached
Mem:      12304936   12200376     104560          0     337276    7082508
-/+ buffers/cache:    4780592    7524344
Swap:      2097144         32    2097112
rwoodrum@util1wad:~/tmp$ uname -a
Linux util1wad 2.6.18-4-amd64 #1 SMP Mon Mar 26 11:36:53 CEST 2007 x86_64 GNU/Linux
rwoodrum@util1wad:~/tmp$ java -version
java version "1.5.0_10"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_10-b03)
Java HotSpot(TM) 64-Bit Server VM (build 1.5.0_10-b03, mixed mode)-ryan woodrum

I've continued to investigate this with my discoveries below. I've found some more interesting nuances, but am still not satisfied with the explanation of what is going on here. For time reasons, I've capitulated to a somewhat lame workaround.
The test run in the 1.6.0 jvm environment is somewhat revealing in that it confirms that the eventual call to fork (I'm kind of guessing it's the fork call here) is returning an ENOMEM. The 1.5.0 jvm was not returning the actual errno from the call in the JNI code. Checking out $linux_src/include/asm-generic/errno-base.h indeed enumerates ENOMEM to 12.
When I saw this, I started looking at the memory commit inside of /proc/meminfo to see what was going on when I would launch the jvm with the varying Xmx and Xms parameters. Somewhat unsurprisingly at this point, when I would run with large a large heap, the Committed_AS would skyrocket by a proportion roughly equal to the fixed heap size. (See here http://lwn.net/Articles/28345/ for an definition of Committed_AS and other /proc/meminfo fields.)
With the above information in hand, I wanted to confirm without a doubt that the kernel was the thorn in my side. So on a test system I started to play around with the vm_overcommit feature - see $linux_src/Documentation/vm/overcommit-accounting for definitions of modes 0,1, and 2). Sure enough, toying with these modes I was able to alter the behavior of launching the jvm. I switched from the default heuristic mode (0) to an "always overcommit" mode and it would launch and sucessfully fork and exec every time. No surprise there.
What IS surprising, however, is that if, under the default heuristic mode, I specify the jvm parameters differently it will sucessfully run and fork and exec the subprocess. It seems odd to me that at the OS level, specifying `java -Xms4g -Xmx4g` will cause the subprocess fork to fail but specifying `java -Xms4g -Xmx5g` will NOT cause the fork to fail. Running with the latter parameters shows the exact same Committed_AS spike. This all begs the question(s): What's the difference? With a min heap size set to 4g (or whatever) on the both jvm runs, how does a jvm parameter (especially one that allows MORE growth of the heap) impact this call to fork? One variable in the picture at this point that I'm unsure of is the strace call to clone(). I don't know what this could be doing to make things behave differently.
So as I noted, above, I have a relatively lame workaround. Blindly add more swap to increase the CommittedLimit inside the kernel. It'll never get used, it's a waste of space, and, perhaps most importantly, on principal it just rubs me the wrong way.
-ryan woodrum

Java.lang.Runtime.exec() again

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