Runtime.exec(String cmd, String[] envp ) is not setting the environment variable PATH

> Is there a way to set the system PATH variable at runtime ?

Create a batch file and execute that.

According to the javadoc what you are doing to set the environment looks about right. What problem are you having?

What is the command, and you executing your command using the command shell, cmd?

You could also specify the absolute path to the app.

Depending on you operating system (Windows 98,2000, etc)it should be something like this:

mRuntime.exec("cmd /c PATH=write something");

The operating system is windows 2000. This is what I tried

mRuntime.exec("cmd /C PATH=c:\\jdk1.3\\jre\\1.3\\bin;c:\\poet80\\runtime\\bin;");


It didn't work

> mRuntime.exec("cmd /C PATH=c:\\jdk1.3\\jre\\1.3\\bin;c:\\poet80\\runtime\\bin;");

Your not running anything?

What is it you r trying to achieve?

I am just trying to set the path variable in my main() mehtod so that the current JVM recognises this path for further execution

you cannot do that.
The exec runs in a new command shell.

you would need to create a batch file that sets the path, before starting the vm.

what do u need to set the path for?

In my application I'm spawning another process to start my server with java.exe. I can pass the classpath as a JVM argument but the process spawned should have some path settings to access some dll files and other processing which is internal to the server. I need to set the path for the server that I spawn.

I can write for you the JNI wrapper for WIN32 ShellExecute or CreateProcess api!

It would be great if I can get the code.....

Thanks in advance

SysUtils.java

public class SysUtils
{
     static
     {
          System.loadLibrary("SysUtils");
     }

     public native static String getEnvironmentVariable(String name);
     public native static void setEnvironmentVariable(String name,String value);
     public native static void shellExecute(String file,String parameters,String directory);
}



SysUtils.cpp

#include <windows.h>
#include <shlobj.h>
#include "SysUtils.h"


JNIEXPORT void JNICALL Java_SysUtils_shellExecute(JNIEnv * env, jclass c, jstring f, jstring p, jstring d)
{
     const char * file=env->GetStringUTFChars(f,0);
     const char * parameters=env->GetStringUTFChars(p,0);
     const char * directory=env->GetStringUTFChars(d,0);
     DWORD res=(DWORD)ShellExecute(NULL,"open",file,parameters,directory,SW_SHOWNORMAL);
     if(res<=32)
     {
          char buffer[256];
          FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM,NULL,GetLastError(),NULL,buffer,256,NULL);
          printf("%s\r\n",buffer);
     }
     env->ReleaseStringUTFChars(f,file);
     env->ReleaseStringUTFChars(p,parameters);
     env->ReleaseStringUTFChars(d,directory);
}

JNIEXPORT jstring JNICALL Java_SysUtils_getEnvironmentVariable(JNIEnv * env, jclass c, jstring n)
{
     char value[4096]={0};
     jstring v;
     const char * name=env->GetStringUTFChars(n,0);
     GetEnvironmentVariable(name,value,4096);
     v=env->NewStringUTF(value);
     env->ReleaseStringUTFChars(n,name);
     return v;
}

JNIEXPORT void JNICALL Java_SysUtils_setEnvironmentVariable(JNIEnv * env, jclass c, jstring n, jstring v)
{
     const char * name=env->GetStringUTFChars(n,0);
     const char * value=env->GetStringUTFChars(v,0);
     SetEnvironmentVariable(name,value);
     env->ReleaseStringUTFChars(n,name);
     env->ReleaseStringUTFChars(v,value);
}



Test.java

public class Test
{
     public static void main(String[] args)
     {
          SysUtils.shellExecute("java","com.myclasses.Server","E:\\JavaProjects\\Server\\");
     }
}

You should specify into the third parameter the directory where yours dll file resides!

This works!

> In my application I'm spawning another process to start my server with java.exe.

Why aren't you just setting the environent using the envp parameter of exec?

I tried with the method exec(String cmd, String[] envp)
This is how I pass the environment variable PATH

mProcess = mRuntime.exec(command, new String[] {"PATH=c:\\jdk1.3\\jre\\1.3\\bin;c:\\poet80\\runtime\\bin;"});

what is the value of command?

The command value is command
"java.exe -classpath c:\poet80runtime\lib\FastObjects_7JC_Runtime.jar;c:\vbroker\vbjava\4.5.1lib\vbjorb.jar;c:\jre\1.3\lib\i18n.jar MyTestApp"

What is wrong with my solution?

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