Setting persitent system environment variables using java program

Question

hai,
Iam tryng to write installation for an application,which require to set some persistent system environment variables using java program. I have tried using set command Runtime.getRuntime().exec("cmd /c set blah blah "),but this applies only to that particular DOS promt only,i presume.And this is not perisistent.please do help.
Biju

Answer 1

The solution I proposed worked only on Windows XP/2003.
The following solution will work on Windows NT/2000/XP/2003 with JDK 1.2+.
1- Download the [url http://www.gjt.org/download/time/java/jnireg/registry-3.1.3.zip]JNIRegistry zipped archive.
2- Open the registry-3.1.3.zip file and extract in the folder of your choice ( Eg. c:\setenv ) only the 2 first files (when sorted by path): ICE_JNIRegistry.dll and registry.jar.
You don't need to keep the folder tree in the extraction.
3- Create the following SetEnv.java file in the same folder ( Eg. c:\setenv ).
import com.ice.jni.registry.Registry;
import com.ice.jni.registry.RegistryKey;
import com.ice.jni.registry.RegStringValue;
import com.ice.jni.registry.RegistryValue;
public class SetEnv
    static final String REG_HKLM_SUBKEY_NAME = "SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Environment";
    public static void main(String[] args)
    throws Exception
        new SetEnv().exec(args);
    void exec(String[] args)
    throws Exception
        if (args.length != 2)
            throw new IllegalArgumentException("\n\nUsage: java SetEnv {varName} {varValue}\n\n");
        String varName = args[0];
        String varValue = args[1];
        RegistryKey key = null;
        RegStringValue value;
        try
            key = Registry.HKEY_LOCAL_MACHINE.openSubKey(REG_HKLM_SUBKEY_NAME, RegistryKey.ACCESS_ALL);
            value = new RegStringValue(key, varName, RegistryValue.REG_EXPAND_SZ);           
            value.setData(varValue);
            key.setValue(value);
            key.flushKey();
        finally
            try { key.closeKey(); }
            catch (Exception e) {}
}4- Compile it.
javac -classpath .;registry.jar SetEnv.java
5- Run it. varName and varValue are strings of your choice.
java -classpath .;registry.jar -Djava.library.path=. SetEnv varName varValue