Question

I’m currently trying to query and set some windows registry entries through a Java app. We are mandated to use the JNI-Registry library (for licensing reasons). The keys and values to set are not under my control (I’m modifying values set by another, 3rd party, application).

I can get and set the various entries and values OK for normal keys and values, and I can query the default value for a key OK. However, I need to know how to set the default values for a key.

//This works
final RegistryKey regKey = Registry.HKEY_LOCAL_MACHINE.openSubKey("SOFTWARE\\company\\app\\subkey", RegistryKey.ACCESS_ALL);
RegStringValue blah = (RegStringValue) regKey.getValue("blah");
if (blah == null) {
    blah = new RegStringValue(regKey, "blah");
}
blah.setData("Some data");
regKey.setValue(blah);

//Not sure about this...
final RegistryKey regKey = Registry.HKEY_LOCAL_MACHINE.openSubKey("SOFTWARE\\company\\app\\subkey", RegistryKey.ACCESS_ALL);
String defaultValue = regKey.getDefaultValue();    //Gets the default value OK
//How do I reset it, though???
//need something like:
//   regKey.setDefaultValue("Some new value");

//The following does not seem to work
RegDWordValue defVal = (RegDWordValue) regKey.getValue(""); //Also tried ...getValue("Default")
defVal.setData("Some new Value");
regKey.setValue(defVal);

regKey.closeKey();

Does anyone know if this is possible?

Answer 1

Yes, its possible.

Well, in c#, for any key, you can do

key.SetValue("", "value");

The nameless key is the default one.

This is documented at: http://msdn.microsoft.com/en-us/library/microsoft.win32.registry.setvalue.aspx (page archived here)

Kinda late, i know. still, hope it helps someone. I was looking for the same thing.