The java.util.prefs.WindowsPreferences is the concrete implementation of AbstractPreferences in the Windows platform. This class provides methods like WindowsRegQueryValueEx, etc. Using Reflection, one can use the methods in this class to query string values under HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER. For some reason, the java wrapper for WindowsRegQueryValueEx only seems to work for string values. I get a null for values of type REG_DWORD, which I guess makes this approach pretty useless except in times of desperation. Please Tell me how I can retrive REG_DWORD values.