import java.lang.reflect.Method;
import java.util.prefs.Preferences;
 
public class JavaRegistry {
    private static final int HKEY_CURRENT_USER = 0x80000001;
    private static final int KEY_QUERY_VALUE = 1;
    private static final int KEY_SET_VALUE = 2;
    private static final int KEY_READ = 0x20019;
 
    public static void main(String args[]) {
        final Preferences userRoot = Preferences.userRoot();
        final Preferences systemRoot = Preferences.systemRoot();
        final Class clz = userRoot.getClass();
 
        try {
            final Method openKey = clz.getDeclaredMethod("openKey",
                    byte[].class, int.class, int.class);
                  openKey.setAccessible(true);
            final Method closeKey = clz.getDeclaredMethod("closeKey",
                    int.class);
            closeKey.setAccessible(true);
 
            final Method winRegQueryValue = clz.getDeclaredMethod(
                    "WindowsRegQueryValueEx", int.class, byte[].class);
            winRegQueryValue.setAccessible(true);
            final Method winRegEnumValue = clz.getDeclaredMethod(
                    "WindowsRegEnumValue1", int.class, int.class, int.class);
            winRegEnumValue.setAccessible(true);
            final Method winRegQueryInfo = clz.getDeclaredMethod(
                    "WindowsRegQueryInfoKey1", int.class);
            winRegQueryInfo.setAccessible(true);
 
            byte[] valb = null;
            String vals = null;
            String key = null;
            Integer handle = -1;
 
 
            key = "HKEY_LOCAL_MACHINE\\SOFTWARE\\Adobe";
            handle = (Integer) openKey.invoke(systemRoot, toCstr(key), KEY_READ, KEY_READ);
            valb = (byte[]) winRegQueryValue.invoke(systemRoot, handle, toCstr("Display Name"));
            vals = (valb != null ? new String(valb).trim() : null);
            System.out.println("Adobe Products = " + vals);
            closeKey.invoke(Preferences.systemRoot(), handle);
            } catch (Exception e) {
            e.printStackTrace();
        }
 
    }
    private static byte[] toCstr(String str) {
        byte[] result = new byte[str.length() + 1];
        for (int i = 0; i < str.length(); i++) {
            result[i] = (byte) str.charAt(i);
        }
        result[str.length()] = 0;
        return result;
    }
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
 
public class WindowsRegistry {
 
 // just read a simple value so far...
 // see reg.exe help (in a command window) for other options
 
 public static String queryValue(String key, String value) {
  // returns null if key/value not found (or other error)
 
  try {
   Process p = new ProcessBuilder("reg.exe", "QUERY", key, "/v", value)
     .redirectErrorStream(true).start();
   // (reg.exe requires parameters to be already tokenised)
   InputStream is = p.getInputStream();
   BufferedReader br = new BufferedReader(new InputStreamReader(is));
 
   String line;
   // scan output & parse interesting lines...
   while ((line = br.readLine()) != null) {
    System.out.println("Input: " + line);
    if (line.contains(value)) {
     // this line displays the value we are looking for
     int i = line.indexOf("REG_SZ");
     if (i >= 0) {
      String result = line.substring(i + 7).trim();
      is.close();
      return result;
     }
    }
    if (line.contains("Error")) {
     System.err.println("reg.exe error searching for: " + key
       + " " + value);
     System.err.println(line);
     is.close();
     return null;
    }
   }
   System.err.println("ERROR: unable to parse output from reg.exe");
   System.err.println("Searching for: " + key + " " + value);
   is.close();
  } catch (Exception e) {
   e.printStackTrace();
  }
  return null;
 }
 
 public static void main(String args[]) throws IOException {
  // a little demo...
  String res;
  res = WindowsRegistry.queryValue("HKCU\\Control Panel\\Desktop",
    "Wallpaper");
  System.out.println("Wallpaper path: \"" + res + "\"");
 
  res = WindowsRegistry.queryValue("HKCU\\Control Panel\\Desktop",
    "noSuchValue");
  System.out.println("Incorrect query returned: \"" + res + "\"");
 }
}