BUG? Can't exit JVM until native Runtime.exec() process exited.

Hi,
Before reporting this as a bug I wanted to hear some opinion.
The problem :
I start a win32 native appllication and then I have to close the VM and leaving the process running.
But inpite any Runtime.exit() or Runtime.halt() call, the vm won't not exit until the proces ends.
Having seen that there could be some issue with the output stream of the process and the VM I tried to redirect it to a file. But still the same.
Any opinion?
Dikran

You have something else going on.
The following code exits and leaves the app running...
    public class TTest
        public static void main(String[] args) throws Exception
        Runtime.getRuntime().exec("notepad");
    }

Similar Messages

Best way to close a Runtime.exec() process and how to handle closing it?

I have multiple Runtime.exec() Processes running and am wondering what the best way it is to close them and take care of closing the resources. I see that Process.destroy() seems to be the way to terminate the Process - is finalize() the best way to close anything in that Process?
Thanks

I was involved with your other thread, so I think I know what you are trying to do.
All Dr's answers are correct.
Now you have a program A written by you that does Runtime.exec() of multiple instances
of another program B written by you. You want A to somehow tell B to exit.
You must use some kind of Inter Process Communication. If this is the only interraction
between the two programs I can suggest two options. If you anticipate more
interraction, you may want to look at other means (RMI, for instance, which was proposed
by EJP in the other thread for starting B, is also useful in exchanging info).
Solution 1:
Start a thread in B and read stdin. A will write to stdin a command, such as QUIT.
When B reads it, it does System.exit().
Solution 2:
Start a SocketServer in B that accepts connections on a separate thread.
When A wants B to exit, it connects to it and writes a command such as QUIT.
When B reads it, it does System.exit().
You may note that QUIT is not the only command you can send from A to B, in case you will need more.
Edited by: baftos on Nov 5, 2007 2:15 PM

Can focus the explorer opened by runtime.exec() ?

Hi all,
I am writing the program that will open the internet explorer
with runtime.exec().
Then, the explorer open successfully.
But i want to set the focus to that explorer.
And can i control the menu bar, status bar of that explorer?
Without using javascript of that webpage, just using java.
Any solution to do this?
Thank for any advise.
Thanks,
Tim.

You can use the hta this way from the command line:
IEStarter.hta http://www.sun.com/
To gain control over the browser appearance from your java-application, just modify the way, the hta uses the command-line parameters. Using the hta this way focuses the newly created browser-window, but doesn't bring it to the front.
Using the Windows Script Host instead brings the new browser window to the front.
Windows Script Host Example: (you just have to type this into the command line)
wscript /nologo IEStarter.js http://java.sun.com/
Source of IEStarter.js
* IEStarter.js (Windows Script Host)
* Usage: wscript /nologo IEStarter.js [Your Url]
//get the url from the command-line
var args = WScript.Arguments;
var newUrl = "";
for (i = 0; i < args.length; i++ )
    newUrl += (i == 0) ? args(i) : " " + args(i);
if (newUrl.length == 0) {
    WScript.Echo(
    "Usage: wscript /nologo IEStarter.js [Your Url]"
} else {
    //create a new browser-instance
    var objExplorer = WScript.CreateObject("InternetExplorer.Application");
    objExplorer.Navigate(newUrl);
    objExplorer.ToolBar = 0;
    objExplorer.StatusBar = 1;
    objExplorer.Width = 700;
    objExplorer.Height = 400;
    objExplorer.Left = 50;
    objExplorer.Top = 50;
    objExplorer.Resizable = 1;
    objExplorer.Visible = 1;
}

Runtime.exec() process executes too fast!

I'm trying to pipe some data into an external process via Process.getOutputStream(). However, this program can operate with or without reading from stdin.
Between the time I run Runtime.exec() and the time I can call Process.getOutputStream(), the process has already decided there's no data coming from stdin and exits.
Is there any way to give a process stdin data before exec'ing?
thanks in advance
Ken

too fast? never heard that complaint before.
Well, either it waits for something on stdin or not. If it determines that there's no stdin that fast, how does it ever wait, cuz no user would type faster then the JVM would get the ouputstream? I mean, if you run it on the command line manually, does it sit and wait? Cuz if not, it's not taking stdin at all. Or are you referring to arguments from the command-line, in which case you need to pass them in the Runtime.exec() method first.

Runtime.exec() process output

I am having strange problems with the output from a program I am executing with Runtime.exec(). This program takes voice input, and generates text output on the commandline. For some reason, I do not see any of the output until the program exits, then everything is displayed. My code is below, any help would be greatly appreciated!
Thanks,
Deena
import java.io.*;
import java.util.*;
//Reads and prints the output streams from an executing process
class ProcessStream extends Thread{
     InputStream is;
     String type;
     ProcessStream(InputStream is, String type){
     this.is = is;
     this.type = type;     //type of output stream, e.g. stdout or stderr
     public void run(){
     try{
          BufferedReader br = new BufferedReader(new InputStreamReader(is));
          String line=null;
               //read and display the output stream of an executing process
          while ((line = br.readLine()) != null){
          System.out.println(type + ">" + line);
     } catch (IOException ioe){
     System.err.println(ioe);
//Interface to TalkBack.exe
public class JTalkBack{
     public static void main(String[] args){
     try{
          String arg="TalkBack.exe -noTTS -noReplay";     //program to execute
          //arguments to program
          for(int i=0; i<args.length; i++){
               arg+=" "+args;
          //execute the program and get an object representing the process
          Process p=Runtime.getRuntime().exec(arg);
          //create stream processors for stdout and stderr of the process
          ProcessStream error = new ProcessStream(p.getErrorStream(), "ERROR");
          ProcessStream output = new ProcessStream(p.getInputStream(), "OUTPUT");
          //start the stream processors
          error.start();
          output.start();
          //wait for the process to finish and get its exit value
          int exitVal = p.waitFor();
     System.out.println("ExitValue: " + exitVal);
     catch (Throwable t){
     System.err.println(t);

I have something similar and it works. The only difference is that I:
1. used a BufferedInputStream instead of the BufferedReader, which means bis.available() and bis.read(buffer) were used instead of .readLine(bis)
2. Didn't print to stdout, but instead fired a proprietary MessageEvent with the string in it to all MessageListeners (good for use with java.util.logging)
3. Didn't (yet) put the input streams in different threads.
Maybe it is related to the fact that you are printing directly back to the System.out again? Does each process in Java get its very own standard out? I don't know.
It's ugly and convoluted, but maybe a snippet of my code will help...
(in run)
Thread myThread = Thread.currentThread();
try {
    proc = r.exec("my_secret_process.exe -arg arg");
    is = new BufferedInputStream(proc.getInputStream());
    while (thread == myThread) {
      int iRead = 0; //how many bytes did we read?
      //message stream check
      if(is.available() > 0) {
        iRead = is.read(buf);
        msg = "\n"+new String(buf, 0, iRead);
        this.fireMessageArrived(new MessageEvent(this, msg));
     } //end while
   } catch(Exception e) {
      System.out.println("Argh. Barf.");
Tarabyte :)

Using runtime.exec,process streams

Hi all,
I am using runtime.exec to execute a batch file(rmdir /s/q directoryname) which deletes all the files in a certain directory(including subdirectories). However, some of the files are not deleted since they are being used by other processes.
I have closed all file references but still the batch file says they are being used by other processes. The File.canWrite() method however, returns true for all the files. I have also tried to delete the files using file.delete but it does not work.
So I have 2 questions.
1. Can I forcibly delete these files some other way.
2. If i call a batch file to delete the files and it fails on some files, the command window displays "cannot delete files". How can I write out thse messages into a text file which i can use as a log file.Do I have to use Process.getInputstream()/Process.getInputstream() ? If so, how?
Thanks for your help.
Vinny

I tried the following before but the string i get is always empty, but i can see there are messages in the command window. Please let me now if i am doing something wrong.
try{
Process p = rt.exec("cmd.exe /c start deletefiles.bat");
InputStream ins = p.getInputStream();
byte[] bytearray = new byte[1024];
int bytecount;
String dos_string="";
BufferedInputStream bis = new BufferedInputStream(ins);
while ((bytecount = bis.read(bytearray, 0, 1024)) > -1) {
String str = new String(bytearray,0,bytecount);
dos_string += str;
System.out.println("dos string is" +dos_string);
catch (Exception e) {
System.out.println("Error: " + e);

Need info about Runtime.exec

Hello, I have a non program specific question about how Runtime.exec works. First off assume that I handle all my input streams and output streams correctly, and I am not worried about inter process communication. The question is, when I use Runtime.getRuntime().exec(cmd[],pth[],dir) does the JVM that is running the code that calls it live until the spawned process dies, or can it die without waiting for the execed process to die? I am trying to write an app that can spawn a new copy of itself that is completely independent from the original process, and may live on long after the original is no longer needed. To ensure proper resource management I need to know that the JVM that launches the new process does not have to wait for the new process to die prior to completely cleaning itself up.
Does that make sense?
Any suggestions, ideas, questions?
Thanks in advance for the help.
Message was edited by:
elixic

Thank you all who gave useful input. I had done some reading on this already and could not find a definite answer on weather or not the calling JVM can properly dispose of itself prior to the process it called being disposed of.
The answer it seems is dependent on context. In windows, and from a GUI app, it looks like the calling JVM can die any time it wants too. A command line app on the other hand seems to have to wait for the app it called to die first. I have not tested it on other OS's but I am sure it varies by OS as well. I would not even be surprised if it varies by JVM.
So the short answer to my question that you all helped me find is this, It varies by context.
Thanks again for the help.
Isaac

Can I redistribute the Adobe AIR Runtime as part of a native installer or with my product's installer?

Hi to All,
Can I redistribute the Adobe AIR Runtime as part of a my
product’s installer? So that if users don't have Adobe Air
runtime installed then the Adobe Air runtime should be installed
first and then simultaneously my adobe air application should be
installed on single click, removing the difficulty of downloading
each installer seperately.
So is there any way so that I can package both Adobe Air
runtime and my application into a single installer file.
Any help or suggestions will be greatly appreciated!.
Thanks in Advance...

You need to apply for it. See the details on how to do this
here:
http://www.mikechambers.com/blog/2008/04/07/redistributing-the-adobe-air-runtime-installer /
-ted

Can't create JVM from JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);

I'm new in using JNI. When i compile the C program that invoke the JAVA program, everthing goes fine. I can obtain the the "exe" from the compilation.
But when i run the "exe" file it display "can't create Java VM". Here is the part of the code in C program:
........//other code
JNI_VERSION_1_2
JavaVMInitArgs vm_args;
JavaVMOption options[1];
options[0].optionString =
"-Djava.class.path=" USER_CLASSPATH;
vm_args.version = 0x00010002;
vm_args.options = options;
vm_args.nOptions = 1;
vm_args.ignoreUnrecognized = JNI_TRUE;
/* Create the Java VM */
res = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);
if (res < 0) {
fprintf(stderr, "Can't create Java VM\n");
exit(1);
.......//other code
I'm using JDK1.3, and windows ME.
Can anyone tell me the problem?

I think you need to get the address of the create function from the jvm.dll at runtime and call that: this works for me:
     HINSTANCE handle;
     JavaVMOption options[5];
     char JREHome[MAX_PATH];
     char JVMPath[MAX_PATH];
     char classpathOption[MAX_PATH];
     char librarypathOption[MAX_PATH];
     if(!GetPublicJREHome(JREHome, MAX_PATH))
          LogError("Could not locate JRE");
          abort();
     strcpy(JVMPath,JREHome);
     strcat(JVMPath,"\\bin\\client\\jvm.dll");
    if ((handle=LoadLibrary(JVMPath))==0)
          LogError("Error loading: %s", JVMPath);
          abort();
    CreateJavaVM_t pfnCreateJavaVM=(CreateJavaVM_t)GetProcAddress(handle,"JNI_CreateJavaVM");
    if (pfnCreateJavaVM==0)
          LogError("Error: can't find JNI interfaces in: %s",JVMPath);
          abort();
     strcpy(classpathOption,"-Djava.class.path=");
     strcat(classpathOption,dir);
     strcat(classpathOption,";");
     strcat(classpathOption,JREHome);
     strcat(classpathOption,"\\lib");
     strcat(classpathOption,";");
     strcat(classpathOption,JREHome);
     strcat(classpathOption,"\\lib\\comm.jar");
     strcpy(librarypathOption,"-Djava.library.path=");
     strcat(librarypathOption,JREHome);
     strcat(librarypathOption,"\\lib");
     OutputDebugString("classpath option=");
     OutputDebugString(classpathOption);
     OutputDebugString("\n");
     OutputDebugString("librarypath option=");
     OutputDebugString(librarypathOption);
     OutputDebugString("\n");
     options[0].optionString=classpathOption;
     options[1].optionString=librarypathOption;
     options[2].optionString="vfprintf";
     options[2].extraInfo=_vfprintf_;
     options[3].optionString="exit";
     options[3].extraInfo=_exit_;
     options[4].optionString="abort";
     options[4].extraInfo=_abort_;
    vmArgs.version = JNI_VERSION_1_2;
    vmArgs.nOptions = 5;
    vmArgs.options = options;
    vmArgs.ignoreUnrecognized = false;
    if(pfnCreateJavaVM(&jvm,(void**)&env, &vmArgs)!=0)
          LogError("Could not create VM");
          abort();
     }

Socket stays open after java process exits, Runtime.exec()

I have a program that does the following:
opens a socket
Does a runtime.exec() of another program
then the main program exits.
what i am seeing is, as long as the exec'd program is running, the socket remains open.
What can i do to get the socket to close?
I even tried to explicity call close() on it, and that didn't work. Any ideas would be great.
I am running this on WindowsXP using netstat to monitor the port utilization.
here is some sample code
import java.io.*;
import java.net.*;
public class ForkTest
    public static void main(String[] args)
        try
            DatagramSocket s = new DatagramSocket(2006);
            Process p = Runtime.getRuntime().exec("notepad.exe");
            System.out.println("Press any key to exit");
            System.in.read();
        catch (IOException ex)
            ex.printStackTrace();
}

java.net.BindException: Address already in use: Cannot bind
        at java.net.PlainDatagramSocketImpl.bind(Native Method)
        at java.net.DatagramSocket.bind(DatagramSocket.java:368)
        at java.net.DatagramSocket.<init>(DatagramSocket.java:210)
        at java.net.DatagramSocket.<init>(DatagramSocket.java:261)
        at java.net.DatagramSocket.<init>(DatagramSocket.java:234)
        at ForkTest.main(ForkTest.java:11)

Runtime.exec() crashes JVM

I wrote a program that runs a Perl script repeatedly via Runtime.exec().
Q: Under what circumstances would this procedure silently crash the JVM? I am experiencing this behavior on Linux using Sun's JDK as well as IBM's. There is no error output. The program simply exits. What is causing this? And, how can it be avoided? If there is a way to recover from whatever problem is occurring, that would be ideal.

Thanks jschell! Your input is helpful.
I suspect that case #4 is in play here. When I run my program with the "-Xrs" switch, "Terminated" is outputted just before the JVM exits. Is there any way to intercept the signal to terminate from the child process before the JVM exits?
NOTE: I am not running Runtime.exec() concurrently and I am explicitly destroying each Process after process.waitFor(). Also, I tend to watch the linux "top" output to confirm that only one Perl process is running at a time. I have tried various versions of a "runCommand" method. The current version spawns no additional threads:
public static int runCommand(String[] command) throws InterruptedException, IOException
          ProcessBuilder builder = new ProcessBuilder(command);
          builder.redirectErrorStream(true);
          Process process = builder.start();
          InputStream input = null;
          InputStream error = null;
          OutputStream output = null;
          BufferedReader reader;
          String line;
          try     {
               input = process.getInputStream();
               error = process.getErrorStream();
               output = process.getOutputStream();
               reader = new BufferedReader(new InputStreamReader(input));
               while ((line = reader.readLine()) != null)
                    System.out.println(line);
               return process.waitFor();
          finally
               close(output);
               close(error);
               close(input);
               process.destroy();
          }

Make can't recursively call Make when run from Runtime.exec (for some user)

This one is a little complicated. The afflicted platform is Mac OS X. It works fine on Linux, it seems, and even then, it does work for some Mac OS X users...
First, the setup. I have a Java program that has to call GNU Make. Then, GNU Make will recursively call Make in some subdirectories. This results in the following Java code:
String make = "make"; //on windows, I have this swapped with "mingw32-make"
String workDir = ...; //this is programmatically detected to be the same folder that the parent Makefile is in
Runtime.getRuntime().exec(make,null,workDir);This calls make on a Makefile which has the following line early on to be executed (this is only a snippet from the makefile):
cd subdirectory && $(MAKE)When I fetch the output from the make command, I usually get what I expect: It cd's to the directory and it recursively calls make and everything goes smoothly.
However, for one particular user, using Mac OS X, he has reported the following output:
cd subdirectory && make
/bin/sh: make: command not found
make: *** [PROJNAME] Error 127Which is like, kinda hurts my head... make can't find make, apparently.
I've gotten some suggestions that it might be due to the "cd" command acting wonky. I've gotten other suggestions that it may be some strange setup with the env variables (My Mac developer is implementing a fix/workaround for 'environ', which is apparently posix standard, but Mac (Mr. Posix Compliance...) doesn't implement it. When he finishes that, I'll know whether it worked or not, but I get the feeling it won't fix this problem, since it's intended for another area of code entirely...
Also worth mentioning, when the user calls "make" from the terminal in said directory, it recurses fine, getting past that particular line. (Later on down the road he hits errors with environ, which is what my aforementioned Mac dev is working on). Although calling "make" by hand is not an ideal solution here.
Anyways, I'm looking for someone who's fairly knowledgeable with Runtime.exec() to suggest some way to work around this, or at least to find out that perhaps one of the User's settings are wonked up and they can just fix it and have this working... that'd be great too.
-IsmAvatar

YoungWinston
YoungWinston wrote:
IsmAvatar wrote:
However, for one particular user, using Mac OS X, he has reported the following output:One particular user, or all users on Mac OS?In this case, I have two mac users. One is reporting that all works fine. The other is reporting this problem.
cd subdirectory && make
/bin/sh: make: command not found
make: *** [PROJNAME] Error 127Which is like, kinda hurts my head... make can't find make, apparently.If that is being reported on the command line, then I'd say that make wasn't being found at all.If make isn't being found, then who's interpreting the Makefile?
It's also just possible that the make script on Mac isn't correctly exporting its PATH variable, though it seems unlikely, since this would surely have been reported as a bug long ago.
I've gotten some suggestions that it might be due to the "cd" command acting wonky...Also seems unlikely. 'cd' has been around since shortly after the K-T extinction event.
WinstonBy "acting wonky", I mean being given a bad work directory or some such, such that it's not changing to the intended directory.
Andrew Thompson
Andrew Thompson wrote:
(shudder) Read and implement all the recommendations of "When Runtime.exec() won't" (http://www.javaworld.com/jw-12-2000/jw-1229-traps.html).
Already read it. I already know the dreadful wonders of Runtime.exec. But in this case, it's been working fine for us up until one Mac user reported that make can't find make.
Also, why are you still coding for Java 1.4? If you are not, use a ProcessBuilder, which takes a small part of the pain out of dealing with processes.Usually I do use a ProcessBuilder. I noticed that it usually delegates to Runtime.exec() anyways, and seeing as I didn't need any of the additional functionality, I decided to just use Runtime.exec() in this particular case.
jschell
jschell wrote:
So print thos env vars, in your app and when the user does it.I'll look into that. It's a good start.
-IsmAvatar

JVM spawning mysterious child process of itself using Runtime.exec()

Hello, I'm not sure if this is how this is supposed to work but I have a java application that monitors legacy c programs and after a period of time (its intermittent), I'll see a duplicate jvm process running the same classpath, classname as a child of the java application monitor. This behaviour can be reproduced with the following simple class running on either solaris 9 or 10 using 1.6.0_03-b05:
public class Monitor {
Process procss;
public Monitor() {
try {
Runtime runtime = Runtime.getRuntime();
for (int i = 0; i < 10000; i++) {
System.out.println("execing command ls -l.");
procss = runtime.exec("ls -l");
procss.waitFor();
catch (Exception e) {
e.printStackTrace();
public static void main(String[] args) {
new Monitor();
Using java -classpath ./ Monitor to run it. While this is running, at intermittent times doing a ps -ef you will see a duplicate jvm running whose parent process is the one that was started on the command line. Ie:
UID PID PPID etc
user 17434 10706 .... java -classpath ./ Monitor (the one I put running)
user 27771 17434 .....java -classpath ./ Monitor (intermittently started)
in another window I'll run the following shell script that will output the processes when a duplicate java process gets started as they don't seem to run very long (on my production system they will occasionally get hung up until I manually kill them):
#!/usr/bin/ksh
while ((1 == 1))
do
ps -ef | grep "Monitor" | grep -v grep > /tmp/test.out
VAL=`cat /tmp/test.out | wc -l`
if (($VAL != 1))
then
echo "Duplicate java process started"
cat /tmp/test.out
fi
done
It takes roughly 30 seconds before I start to see duplicate jvms starting to run. The concern is that is the new jvm instance running the Monitor class? Eventually on my production system the real application will have a child or 2 linger indefinetly, and threads will be deadlocked. Once I kill these child java processes, everything is back to normal. This doesn't seem to occur with the above java class but will show the duplicate child jvm's start to run after a bit.

This is true for Solaris and Linux. Sun's implementation does a fork. A lot of people who have very large memory java applications wish there was a way to create a process from Java that doesn't involve copying the parent process. As far as I know your stuck.
A workaround: Use jms, rmi, sockets, or files to communicate with a low memory footprint java application whose sole purpose is to spawn child processes.

Can we run a java application using Runtime.exec()?

Can we run a java application using Runtime.exec()?
If yes what should i use "java" or "javaw", and which way?
r.exec("java","xyz.class");

The best way to run the java application would be to dynamiically load it within the same JVM. Look thru the class "ClassLoader" and the "Class", "Method" etc...clases.
The problem with exec is that it starts another JVM and moreover you dont have the interface where you can throw the Output directly.(indirectly it can be done by openong InputStreams bala blah............). I found this convenient. I am attaching part of my code for easy refernce.
HIH
ClassLoader cl = null;
Class c = null;
Class cArr[] ;
Method md = null;
Object mArr[];
cl = ClassLoader.getSystemClassLoader();
try{
     c = cl.loadClass(progName.substring(0,progName.indexOf(".class")) );
} catch(ClassNotFoundException e) {
System.out.println(e);
     cArr = new Class[1] ;
     try{
     cArr[0] = Class.forName("java.lang.Object");
     } catch(ClassNotFoundException e) {
     System.out.println(e);
     mArr = new Object[1];
     try{
     md = c.getMethod("processPkt", cArr);
     } catch(NoSuchMethodException e) {
     System.out.println(e);
     } catch(SecurityException e) {
     System.out.println(e);
try {
processedPkt = md.invoke( null, mArr) ;
} catch(IllegalAccessException e) {
          System.out.println(e);
} catch(IllegalArgumentException e) {
          System.out.println(e);
}catch(InvocationTargetException e) {
          System.out.println(e);
}catch(NullPointerException e) {
          System.out.println(e);
}catch(ExceptionInInitializerError e) {
          System.out.println(e);
}

I can't exit Mini Player in iTunes 11

It's simple really. I can enter Mini Player using Ctrl+Shift+M but then I can't exit it. I can bypass it by pressing "Go to *artist*" but it still doesn't close.

I am having the same problem that the person who started the thread is having. iTunes 11 is horribly broken on many levels. I recommend uninstalling and reinstalling iTunes 10 until they figure out what they are doing. @Barrie Newcombe - I'm sure many people run the software without this particular problem. I don't think Apple would release software that never worked for anybody. Those of us who are experiencing the problem are looking for information regarding the problem we are experiencing.

BUG? Can't exit JVM until native Runtime.exec() process exited.

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